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1.
Bioprocess Biosyst Eng ; 44(1): 185-193, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32895870

RESUMO

Polyhydroxybutyrate (PHB) is a biodegradable bioplastic that is comparable with many petroleum-based plastics in terms of mechanical properties and is highly biocompatible. Lignocellulosic biomass conversion into PHB can increase profit and add sustainability. Glucose, xylose and arabinose are the main monomer sugars derived from upstream lignocellulosic biomass processing. The sugar mixture ratios may vary greatly depending on the pretreatment and enzymatic hydrolysis conditions. Paraburkholderia sacchari DSM 17165 is a bacterium strain that can convert all three sugars into PHB. In this study, fed-batch mode was applied to produce PHB on three sugar mixtures (glucose:xylose:arabinose = 4:2:1, 2:2:1, 1:2:1). The highest PHB concentration produced was 67 g/L for 4:2:1 mixture at 41 h corresponding to an accumulation of 77% of cell dry weight as PHB. Corresponding sugar conversion efficiency and productivity were 0.33 g PHB/g sugar consumed and 1.6 g/L/h, respectively. The results provide references for process control to maximize PHB production from real sugar streams derived from corn fibre.


Assuntos
Arabinose/metabolismo , Técnicas de Cultura Celular por Lotes , Burkholderiaceae/crescimento & desenvolvimento , Glucose/metabolismo , Polímeros/metabolismo , Xilose/metabolismo , Arabinose/farmacologia , Glucose/farmacologia , Xilose/farmacologia
2.
Ophthalmology ; 127(8): 1012-1019, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32386810

RESUMO

PURPOSE: To report the 3-month results of a randomized trial (Femtosecond Laser-Assisted Cataract Trial [FACT]) comparing femtosecond laser-assisted cataract surgery (FLACS) with standard phacoemulsification cataract surgery (PCS). DESIGN: Multicenter, randomized controlled trial funded by the UK National Institute of Health Research (HTA 13/04/46/). PARTICIPANTS: Seven hundred eighty-five patients with age-related cataract. METHODS: This trial took place in 3 hospitals in the UK National Health Service (NHS). Randomization (1:1) was stratified by site, surgeon, and 1 or both eyes eligible using a secure web-based system. Postoperative assessments were masked to the allocated intervention. The primary outcome was unaided distance visual acuity (UDVA) in the study eye at 3 months. Secondary outcomes included corrected distance visual acuity, complications, and patient-reported outcomes measures. The noninferiority margin was 0.1 logarithm of the minimum angle of resolution (logMAR). ISRCTN.com registry, number ISRCTN77602616. MAIN OUTCOME MEASURES: We enrolled 785 participants between May 2015 and September 2017 and randomly assigned 392 to FLACS and 393 to PCS. At 3 months postoperatively, mean UDVA difference between treatment arms was -0.01 logMAR (-0.05 to 0.03), and mean corrected distance visual acuity difference was -0.01 logMAR (95% confidence interval [CI], -0.05 to 0.02). Seventy-one percent of both FLACS and PCS cases were within ±0.5 diopters (D) of the refractive target, and 93% of FLACS and 92% of PCS cases were within ±1.0 D. There were 2 posterior capsule tears in the PCS arm and none in the FLACS arm. There were no significant differences between arms for any secondary outcome. CONCLUSIONS: Femtosecond laser-assisted cataract surgery is not inferior to conventional PCS surgery 3 months after surgery. Both methods are as good in terms of vision, patient-reported health, and safety outcomes at 3 months. Longer-term outcomes of the clinical effectiveness and cost-effectiveness are awaited.


Assuntos
Terapia a Laser/métodos , Facoemulsificação/métodos , Acuidade Visual , Idoso , Análise Custo-Benefício , Feminino , Seguimentos , Humanos , Masculino , Facoemulsificação/economia , Estudos Retrospectivos , Resultado do Tratamento
3.
Bioprocess Biosyst Eng ; 42(9): 1495-1506, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31111213

RESUMO

Conversion of lignocellulosic feedstocks to polyhydroxybutyrate (PHB) could make lignocellulosic biorefineries more profitable and sustainable. Glucose, xylose and arabinose are the main sugars derived from pretreatment and hydrolysis of herbaceous feedstocks. Burkholderia sacchari DSM 17165 is a bacterium that can convert these sugars into PHB. However, the effects of sugar ratio, sugar concentration, and molar C:N ratio on PHB production have not been studied. In this study, a seven-run mixture design for sugar ratio combined with a 32 full factorial design for process variables was performed to optimize PHB production. A polynomial model was built based on experimental data, and optimum conditions for different sugar streams were derived and validated. The highest PHB production (3.81 g/L) was achieved with arabinose at a concentration of 25.54 g/L and molar C:N ratio of 74.35. Results provide references for manipulation of sugar mixture and process control to maximize PHB production.


Assuntos
Arabinose/farmacologia , Burkholderiaceae/crescimento & desenvolvimento , Glucose/farmacologia , Polímeros/metabolismo , Xilose/farmacologia , Arabinose/química , Glucose/química , Xilose/química
4.
Graefes Arch Clin Exp Ophthalmol ; 255(1): 135-139, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27722920

RESUMO

PURPOSE: Recently, optical coherence tomography angiography (OCTA) has been used to successfully delineate vessels within the retina. This current study aims to assess corneal vascularization secondary to herpetic keratitis pre- and post-treatment using serial OCTA imaging adapted for the anterior segment. METHODS: All eyes were scanned using the split-spectrum amplitude decorrelation angiography (SSADA) algorithm on the AngioVue OCTA system (Optovue Inc. Fremont, CA, USA) with an anterior segment lens adapter. Multiple scans in the regions of interest (ROI) before and after treatment were analysed to assess change in corneal vascularization in response to each treatment modality. RESULTS: We analyzed a total of 12 OCTA scans in three eyes with corneal vascularization, comparing images pre- and 3 months post-treatment. We found that the OCTA was able to detect a significant decrease in area of vascularization in all eyes: including fine-needle diathermy (48 ± 7 to 41 ± 5 %, P = 0.048), subconjunctival bevacizumab (45 ± 7 to 38 ± 5 %, P = 0.015) and systemic steroid treatment following graft rejection (38 ± 1 to 32 ± 2 %, P = 0.003). CONCLUSIONS: Our preliminary study of serial OCTA scans suggests that this may be a useful tool for objective quantification of corneal vascularization. Future development of image processing software will be needed for clinical use or trials to evaluate anti-vascular therapies.


Assuntos
Angiografia/métodos , Córnea/irrigação sanguínea , Neovascularização da Córnea/diagnóstico , Tomografia de Coerência Óptica/métodos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Reprodutibilidade dos Testes
5.
J Ind Microbiol Biotechnol ; 44(2): 247-257, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27999967

RESUMO

Aryl alcohol oxidase (MtGloA) is an enzyme that belongs to the ligninolytic consortium and can play an important role in the bioenergy industry. This study investigated production of an MtGloA client enzyme by a mutant strain of Aspergillus nidulans unable to synthesize its own pyridoxine. Pyridoxine limitation can be used to control cell growth, diverting substrate to protein production. In agitated culture, enzyme production was similar when using media with 1 mg/L and without pyridoxine (26.64 ± 6.14 U/mg mycelia and 26.14 ± 8.39 U/mg mycelia using media with and without pyridoxine, respectively). However, the treatment lacking pyridoxine had to be supplemented with pyridoxine after 156 h of fermentation to sustain continued enzyme production. Use of extremely diluted pyridoxine levels allowed reduced fungal growth while maintaining steady enzyme production. Concentrations of 9 and 13.5 µg/L pyridoxine allowed MtGloA production with a growth rate of only 5% of that observed when using the standard 1 mg/L pyridoxine media.


Assuntos
Oxirredutases do Álcool/biossíntese , Aspergillus nidulans/enzimologia , Aspergillus nidulans/genética , Meios de Cultura/química , Fermentação , Concentração de Íons de Hidrogênio , Microbiologia Industrial , Piridoxina/metabolismo
6.
Ophthalmology ; 122(9): 1740-7, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26088621

RESUMO

PURPOSE: To evaluate the application of an optical coherence tomography angiography (OCTA) system adapted for the assessment of anterior segment vasculature. DESIGN: Cross-sectional, observational study. PARTICIPANTS: Consecutive subjects with normal eyes on slit-lamp clinical examination and patients with abnormal corneal neovascularization. METHODS: All scans were performed using a commercially available AngioVue OCTA system (Optovue, Inc., Fremont, CA) using an anterior segment lens adapter and the split-spectrum amplitude decorrelation angiography algorithm. Each subject underwent scans from 4 quadrants (superior, inferior, nasal, and temporal) in each eye by 2 trained, independent operators. MAIN OUTCOME MEASURES: Analysis of signal strength, image quality, and reproducibility of corneal vascular measurements was performed. RESULTS: In our study of 20 normal subjects (10 men, 10 women; mean age, 25.3±7.8 years), we found good repeatability (κ coefficient, 0.76) for image quality score and good interobserver agreement for vasculature measurements (intraclass coefficient, 0.94). After optimization of the angiography scan protocol, vascular measurements within the regions of interest were compared in the superior versus inferior quadrants (mean vascular loops, 3.34±1.16 vs. 3.12 ± 0.90 [P = 0.768]; segment-to-loop ratio, 4.18±0.71 vs. 4.32±0.87 [P = 0.129]; fractal dimension [Df] value, 1.78±0.06 vs. 1.78±0.06 [P = 0.94]; vascular loop area, 25.9±14.5 vs. 25.9±10.7 × 10(-3) mm(2) [P = 0.21]) and nasal versus temporal quadrant (mean vascular loops, 2.89±0.98 vs. 3.57±0.99 [P < 0.001]; segment-to-loop ratio, 3.94±0.69 vs. 4.55±0.78 [P = 0.897]; Df value, 1.78±0.06 vs. 1.77±0.06 [P = 0.14]; vascular loop area, 29.7±15.7 vs. 22.1±7.1 × 10(-3) mm(2) [P = 0.38]. We then used the established OCTA scanning protocol to visualize abnormal vasculature successfully in 5 patients with various corneal pathologic features, including graft-associated neovascularization, postherpetic keratitis scarring, lipid keratopathy, and limbal stem cell deficiency. CONCLUSIONS: This preliminary study describes a method for acquiring OCTA images of the cornea and limbal vasculature with substantial consistency. This technique may be useful for the objective evaluation of corneal neovascularization in the future.


Assuntos
Segmento Anterior do Olho/irrigação sanguínea , Angiofluoresceinografia , Fluxo Sanguíneo Regional/fisiologia , Tomografia de Coerência Óptica , Adulto , Neovascularização da Córnea/fisiopatologia , Estudos Transversais , Diagnóstico por Imagem/métodos , Feminino , Voluntários Saudáveis , Humanos , Masculino , Microcirculação/fisiologia , Pessoa de Meia-Idade , Pterígio/fisiopatologia , Adulto Jovem
7.
J Ind Microbiol Biotechnol ; 41(10): 1563-70, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25085742

RESUMO

The present study investigated the limitation of pyridoxine on an Aspergillus nidulans culture that produces xylanase B (XynB) as a client enzyme and was unable to synthesize pyridoxine. This technique was used to limit cell growth and divert substrate to product formation for a surface grown culture that could be used in trickle bed reactors. It was observed that growth was limited when pyridoxine was absent, while enzyme production was unaffected. Enzyme production was 1,026 U after 480 h of continuous fermentation, which was similar to a culture that grew on medium with pyridoxine. Furthermore, the present study investigated the growth rate of A. nidulans with pyridoxine in the medium and determined the productivity of XynB production with and without pyridoxine. A maximum growth rate of 0.311/h was observed. The maximum XynB productivity of 21.14 U/g h was achieved when pyridoxine was not added to the medium.


Assuntos
Aspergillus nidulans/enzimologia , Endo-1,4-beta-Xilanases/biossíntese , Proteínas Fúngicas/biossíntese , Piridoxina/metabolismo , Aspergillus nidulans/crescimento & desenvolvimento , Meios de Cultura , Fermentação , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Maltose/metabolismo , Proteínas Recombinantes/biossíntese
8.
Enzyme Microb Technol ; 174: 110392, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38171172

RESUMO

Lignin depolymerization, which enables the breakdown of a complex and heterogeneous aromatic polymer into relatively uniform derivatives, serves as a critical process in valorization of lignin. Enzymatic lignin depolymerization has become a promising biological strategy to overcome the heterogeneity of lignin, due to its mild reaction conditions and high specificity. However, the low solubility of lignin compounds in aqueous environments prevents efficient lignin depolymerization by lignin-degrading enzymes. The employment of biocompatible ionic liquids (ILs) and deep eutectic solvents (DESs) in lignin fractionation has created a promising pathway to enzymatically depolymerize lignin within these green solvents to increase lignin solubility. In this review, recent research progress on enzymatic lignin depolymerization, particularly in a consolidated process involving ILs/DESs is summarized. In addition, the interactions between lignin-degrading enzymes and solvent systems are explored, and potential protein engineering methodology to improve the performance of lignin-degrading enzymes is discussed. Consolidation of enzymatic lignin depolymerization and biocompatible ILs/DESs paves a sustainable, efficient, and synergistic way to convert lignin into value-added products.


Assuntos
Líquidos Iônicos , Lignina , Solventes Eutéticos Profundos , Biomassa , Solventes
9.
Appl Environ Microbiol ; 79(15): 4620-34, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23709508

RESUMO

Anaerobic gut fungi represent a distinct early-branching fungal phylum (Neocallimastigomycota) and reside in the rumen, hindgut, and feces of ruminant and nonruminant herbivores. The genome of an anaerobic fungal isolate, Orpinomyces sp. strain C1A, was sequenced using a combination of Illumina and PacBio single-molecule real-time (SMRT) technologies. The large genome (100.95 Mb, 16,347 genes) displayed extremely low G+C content (17.0%), large noncoding intergenic regions (73.1%), proliferation of microsatellite repeats (4.9%), and multiple gene duplications. Comparative genomic analysis identified multiple genes and pathways that are absent in Dikarya genomes but present in early-branching fungal lineages and/or nonfungal Opisthokonta. These included genes for posttranslational fucosylation, the production of specific intramembrane proteases and extracellular protease inhibitors, the formation of a complete axoneme and intraflagellar trafficking machinery, and a near-complete focal adhesion machinery. Analysis of the lignocellulolytic machinery in the C1A genome revealed an extremely rich repertoire, with evidence of horizontal gene acquisition from multiple bacterial lineages. Experimental analysis indicated that strain C1A is a remarkable biomass degrader, capable of simultaneous saccharification and fermentation of the cellulosic and hemicellulosic fractions in multiple untreated grasses and crop residues examined, with the process significantly enhanced by mild pretreatments. This capability, acquired during its separate evolutionary trajectory in the rumen, along with its resilience and invasiveness compared to prokaryotic anaerobes, renders anaerobic fungi promising agents for consolidated bioprocessing schemes in biofuels production.


Assuntos
Bovinos/microbiologia , Evolução Molecular , Genoma Fúngico , Neocallimastigales/genética , Rúmen/microbiologia , Adaptação Fisiológica , Animais , Biomassa , Bovinos/metabolismo , Celulose/metabolismo , Fezes/microbiologia , Fermentação , Masculino , Dados de Sequência Molecular , Neocallimastigales/classificação , Neocallimastigales/metabolismo , Filogenia , Rúmen/metabolismo , Análise de Sequência de DNA , Análise de Sequência de Proteína , Homologia de Sequência
10.
Ophthalmology ; 120(12): 2449-2455.e1, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24070808

RESUMO

OBJECTIVE: To compare spectacle independence in patients randomized to receive bilateral multifocal intraocular lenses (IOLs) or monofocal IOLs with the powers adjusted to produce monovision. DESIGN: Randomized, multicenter clinical trial. PARTICIPANTS: A total of 212 patients with bilateral, visually significant cataract. METHODS: Before bilateral sequential cataract surgery, patients were randomized (allocation ratio 1:1) to receive bilateral Tecnis ZM900 diffractive multifocal lenses (Abbott Medical Optics, Santa Ana, CA) or Akreos AO monofocal lenses (Bausch & Lomb, Rochester, NY) with the powers adjusted to target -1.25 diopters (D) monovision. Outcomes were assessed 4 months after the second eye underwent operation. MAIN OUTCOME MEASURES: The primary outcome was spectacle independence. Secondary outcomes included questionnaires (VF-11R, dysphotopsia symptoms, and satisfaction) and visual function measures (near, intermediate, and distance logarithm of minimum angle of resolution [logMAR] visual acuity, stereoacuity, contrast sensitivity, and forward light scatter). RESULTS: A total of 212 patients were randomized, and 187 patients (88%) returned for assessment 4 months after surgery. Uniocular distance refractions in the monovision arm showed a mean spherical equivalent of +0.075 D in the distance eye and -0.923 in the near eye. In the multifocal arm, the mean distance spherical equivalents were -0.279 D and -0.174 D in the right and left eyes, respectively. A total of 24 of 93 patients (25.8%) in the monovision arm and 67 of 94 patients (71.3%) in the multifocal arm reported never wearing glasses (P<0.001, Fisher exact test). The adjusted odds ratio of being spectacle free was 7.51 (95% confidence interval, 3.89-14.47). Binocular uncorrected acuities did not differ significantly for distance (0.058 logMAR for monovision vs. 0.076 for multifocal, P = 0.3774) but were significantly worse in the multifocal arm for intermediate acuity (0.149 vs. 0.221, P = 0.0001) and in the monovision arm for near acuity (0.013 vs. -0.025, P = 0.037). In the first postoperative year, 6 patients (5.7%) in the multifocal arm underwent IOL exchange (4 had a bilateral and 2 had a unilateral exchange). No patients in the monovision arm underwent IOL exchange. CONCLUSIONS: Patients randomized to bilateral implantation with the diffractive multifocal Tecnis ZM900 were more likely to report being spectacle independent but also more likely to undergo IOL exchange than those randomized to receive monofocal implants (Akreos AO) with the powers adjusted to give low monovision.


Assuntos
Catarata/fisiopatologia , Implante de Lente Intraocular , Lentes Intraoculares , Facoemulsificação , Pseudofacia/fisiopatologia , Idoso , Sensibilidades de Contraste/fisiologia , Método Duplo-Cego , Óculos/estatística & dados numéricos , Feminino , Humanos , Masculino , Desenho de Prótese , Resultado do Tratamento , Visão Binocular/fisiologia , Acuidade Visual/fisiologia
11.
Eye (Lond) ; 37(11): 2316-2319, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-36481958

RESUMO

PURPOSE: The aim of the study was to present the rates of corneal transplant rejection from 2018 to 2022 at both Moorfields Eye Hospital UK, and Ospedali Privati Forli (OPF) "Villa Igea", Italy and evaluate the purported association between COVID-19 vaccination and rejection. METHODS: We performed a retrospective review of rejection cases presenting to the two units. Monthly rates were correlated against regional vaccination programme rates. At OPF, conditional Poisson regression model was employed to estimate the incidence risk ratio (IRR) of graft rejection following COVID-19 vaccination risk period compared with the control period. RESULTS: Between January 2018 and March 2022, there were 471 (Moorfields), 95 (OPF) episodes of rejection. From the start of vaccination programme in the UK in late January 2021, the median number of graft rejections per month at Moorfields was 6 (range: 5-9), which was not significantly different to post-lockdown, pre-vaccination programme (March 2020-January 2021), p = 0.367. At OPF, the median rates of rejection before and after initiation of the vaccination programme were not significantly different (p = 0.124). No significant increase in incidence rate of rejection in the risk period following COVID-19 vaccination was found (IRR = 0.53, p = 0.71). CONCLUSION: No notable increase in rates of transplant rejection was noted in year 2021 when COVID-19 vaccination was broadly implemented. The apparent temporal relationship between COVID-19 vaccination and corneal graft rejection highlighted in several case reports may not represent a causative association.


Assuntos
COVID-19 , Doenças da Córnea , Humanos , Rejeição de Enxerto , Vacinas contra COVID-19 , Controle de Doenças Transmissíveis , Complicações Pós-Operatórias , Vacinação , Transtornos da Visão
12.
Biotechnol Bioeng ; 109(11): 2720-8, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22566280

RESUMO

Clostridium carboxidivorans P7 is one of three microbial catalysts capable of fermenting synthesis gas (mainly CO, CO(2) , and H(2) ) to produce the liquid biofuels ethanol and butanol. Gasification of feedstocks to produce synthesis gas (syngas), followed by microbial conversion to solvents, greatly expands the diversity of suitable feedstocks that can be used for biofuel production beyond commonly used food and energy crops to include agricultural, industrial, and municipal waste streams. C. carboxidivorans P7 uses a variation of the classic Wood-Ljungdahl pathway, identified through genome sequence-enabled approaches but only limited direct metabolic analyses. As a result, little is known about gene expression and enzyme activities during solvent production. In this study, we measured cell growth, gene expression, enzyme activity, and product formation in autotrophic batch cultures continuously fed a synthetic syngas mixture. These cultures exhibited an initial phase of growth, followed by acidogenesis that resulted in a reduction in pH. After cessation of growth, solventogenesis occurred, pH increased and maximum concentrations of acetate (41 mM), butyrate (1.4 mM), ethanol (61 mM), and butanol (7.1 mM) were achieved. Enzyme activities were highest during the growth phase, but expression of carbon monoxide dehydrogenase (CODH), Fe-only hydrogenases and two tandem bi-functional acetaldehyde/alcohol dehydrogenases were highest during specific stages of solventogenesis. Several amino acid substitutions between the tandem acetaldehyde/alcohol dehydrogenases and the differential expression of their genes suggest that they may have different roles during solvent formation. The data presented here provide a link between the expression of key enzymes, their measured activities and solvent production by C. carboxidivorans P7. This research also identifies potential targets for metabolic engineering efforts designed to produce higher amounts of ethanol or butanol from syngas. .


Assuntos
Clostridium/fisiologia , Gases/metabolismo , Regulação Fúngica da Expressão Gênica , Solventes/metabolismo , Estresse Fisiológico , Acetatos/metabolismo , Reatores Biológicos/microbiologia , Butanóis/metabolismo , Butiratos/metabolismo , Dióxido de Carbono/metabolismo , Monóxido de Carbono/metabolismo , Clostridium/crescimento & desenvolvimento , Clostridium/metabolismo , Enzimas/metabolismo , Etanol/metabolismo , Perfilação da Expressão Gênica , Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio
13.
Int Ophthalmol ; 32(5): 459-60, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22733251

RESUMO

A 45-year-old woman presented with a traumatic laser-assisted in situ keratomileusis (LASIK) flap dislocation in the right eye. Anterior segment optical coherence tomography (OCT) showed the presence of macrostriae, flap stromal edema, epithelial hyperplasia between the striae and epithelial ingrowth. The flap was surgically repositioned with optimal visual recovery. Anterior segment OCT can efficiently visualize corneal structural changes associated with LASIK flap dislocation.


Assuntos
Córnea/cirurgia , Traumatismos Oculares/complicações , Ceratomileuse Assistida por Excimer Laser In Situ/métodos , Miopia/cirurgia , Retalhos Cirúrgicos , Deiscência da Ferida Operatória/etiologia , Tomografia de Coerência Óptica/métodos , Córnea/patologia , Traumatismos Oculares/diagnóstico , Feminino , Humanos , Pessoa de Meia-Idade , Deiscência da Ferida Operatória/diagnóstico
14.
Bioresour Technol ; 364: 128045, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36182017

RESUMO

Worldwide demand for renewable energy has promoted the considerable exploration of biofuel production from lignocellulosic biomass. Ionic liquid pretreatment is of great interest to render biomass amenable for biofuel production, however, its unaffordable cost stimulates significant attention to the feasibility of commercialization. This review aims to compile the latest advances with respect to reducing production costs for ionic liquids-based biorefineries. Protic ionic liquids offer relatively low synthesis costs, but excessive antisolvent washing of the pretreated biomass is often inevitable. Recovering ionic liquids requires several separation and purification steps, and the reuse of ionic liquids could significantly lose functionality due to the degradation. It is promising to screen ionic liquids-tolerant enzymes and strains for one-pot saccharification and fermentation without solid-liquid separation, however, there is still a need for subsequent recovery of ionic liquids. Additionally, technoeconomic analysis and life cycle assessment are highly recommended to evaluate the economic and environmental impacts.

15.
Am J Ophthalmol ; 240: 23-29, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35227697

RESUMO

PURPOSE: To evaluate the clinical results of Descemet membrane endothelial keratoplasty (DMEK) without any intraoperative or postoperative posturing. DESIGN: Retrospective, noncomparative, and interventional case series. METHODS: One hundred thirty-four (134) consecutive eyes of 101 patients requiring DMEK for any cause of endothelial failure were included. Descemet membrane endothelial keratoplasty was performed with an intraoperative inferior PI. After unscrolling and centration of the graft, the anterior chamber was near completely filled with 20% SF6. After filling the eye with gas there was no intraoperative tamponade time, and patients did not posture postoperatively. Main outcome measures were: graft detachment rate, rebubbling rate, primary and secondary failure rates, rejection rate, intraoperative and postoperative complications, and visual acuity 3 and 12 months after surgery. RESULTS: Five of 134 (3.7%) developed graft detachment greater than one-third of the graft area, and 19 of 134 (14.2%) developed graft detachment less than one-third of the graft area. A rebubble procedure was performed in 19 of 134 (14.2%); of those, the average number of rebubbling procedures performed was 1.13 (range, 1-2). Primary failure occurred in 6 of 134 (4.5%).Twelve-month graft survival occurred in 122 of 134 eyes (91.0%), with secondary failure within the first 12 months accounting for failure of 6 of 134 (4.5%). Nine of 134 (6.7%) cases had a recorded episode of endothelial rejection. The average time for rejection episode was 9.5 months (range, 1-20 months) after surgery. CONCLUSIONS: A total of 134 'posture-less' DMEKs did not suffer very high rates of graft detachment, rebubbling, or other postoperative complications, even with immediate erect posturing after surgery.


Assuntos
Ceratoplastia Endotelial com Remoção da Lâmina Limitante Posterior , Lâmina Limitante Posterior/cirurgia , Ceratoplastia Endotelial com Remoção da Lâmina Limitante Posterior/métodos , Endotélio Corneano , Rejeição de Enxerto/cirurgia , Sobrevivência de Enxerto , Humanos , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos
16.
Biotechnol Bioeng ; 108(10): 2330-8, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21557204

RESUMO

Gasification-fermentation is an emerging technology for the conversion of lignocellulosic materials into biofuels and specialty chemicals. For effective utilization of producer gas by fermenting bacteria, tar compounds produced in the gasification process are often removed by wet scrubbing techniques using acetone. In a preliminary study using biomass generated producer gas scrubbed with acetone, an accumulation of acetone and subsequent isopropanol production was observed. The effect of 2 g/L acetone concentrations in the fermentation media on growth and product distributions was studied with "Clostridium ragsdalei," also known as Clostridium strain P11 or P11, and Clostridium carboxidivorans P7 or P7. The reduction of acetone to isopropanol was possible with "C. ragsdalei," but not with P7. In P11 this reaction occurred rapidly when acetone was added in the acidogenic phase, but was 2.5 times slower when added in the solventogenic phase. Acetone at concentrations of 2 g/L did not affect the growth of P7, but ethanol increased by 41% and acetic acid concentrations decreased by 79%. In the fermentations using P11, growth was unaffected and ethanol concentrations increased by 55% when acetone was added in the acidogenic phase. Acetic acid concentrations increased by 19% in both the treatments where acetone was added. Our observations indicate that P11 has a secondary alcohol dehydrogenase that enables it to reduce acetone to isopropanol, while P7 lacks this enzyme. P11 offers an opportunity for biological production of isopropanol from acetone reduction in the presence of gaseous substrates (CO, CO2, and H2).


Assuntos
2-Propanol/metabolismo , Acetona/metabolismo , Dióxido de Carbono/metabolismo , Monóxido de Carbono/metabolismo , Clostridium/metabolismo , Hidrogênio/metabolismo , Oxirredução
17.
Bioresour Technol ; 325: 124700, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33461124

RESUMO

Enzymatic lignin depolymerization is considered a favorable approach to utilize lignin due to the higher selectivity and less energy requirement when compared to thermochemical lignin valorization. Lignin peroxidase (LiP) is one of the key enzymes involved in lignin degradation and possesses high redox potential to oxidize non-phenolic structures and phenolic compounds in lignin. However, the production of LiP is mainly from white-rot fungi at small scales. It is critical to discover new LiP from other microorganisms and produce LiP at large scales. This study aims to produce a novel LiP originally from Thermothelomyces thermophiles using a recombinant Aspergillus nidulans strain. The LiP production medium was optimized, and different fed-batch strategies for LiP production were investigated to improve LiP activity, yield, and productivity. Results demonstrated that LiP production was enhanced by using multi-pulse fed-batch fermentation. A maximum LiP activity of 1,645 mU/L with a protein concentration of 0.26 g/L was achieved.


Assuntos
Aspergillus nidulans , Aspergillus nidulans/genética , Reatores Biológicos , Lignina , Peroxidases/genética , Sordariales
18.
Bioresour Technol ; 338: 125564, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34284293

RESUMO

Enzymatic depolymerization of lignin to produce low molecular weight products requires mild reaction conditions and exhibits higher selectivity compared to thermochemical lignin depolymerization. However, it remains challenging to depolymerize lignin enzymatically, partially due to the low solubility of lignin in aqueous phase. This study aimed to develop a novel approach to combine aqueous lignin extraction with enzymatic lignin depolymerization in biocompatible ionic liquids. A bi-enzyme system containing aryl alcohol oxidase (AAO) and lignin peroxidase (LiP) was developed to depolymerize lignin. Temperature and pH profiles for LiP and AAO were determined. Biocompatibilities of LiP and AAO in different deep eutectic solvents and ionic liquids were investigated. Aqueous cholinium glycinate was found to be an efficient and suitable solvent to solubilize lignin and serve as a biocompatible medium for enzymes to work. LiP and AAO together reduced lignin molecular weight in both solid and liquid phase after enzymatic lignin depolymerization.


Assuntos
Líquidos Iônicos , Oxirredutases do Álcool , Lignina , Peroxidases
19.
PLoS One ; 16(5): e0245407, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33939701

RESUMO

Within the field of bioproduction, non-model organisms offer promise as bio-platform candidates. Non-model organisms can possess natural abilities to consume complex feedstocks, produce industrially useful chemicals, and withstand extreme environments that can be ideal for product extraction. However, non-model organisms also come with unique challenges due to lack of characterization. As a consequence, developing synthetic biology tools, predicting growth behavior, and building computational models can be difficult. There have been many advancements that have improved work with non-model organisms to address broad limitations, however each organism can come with unique surprises. Here we share our work in the non-model bacterium Actinobacillus succinognes 130Z, which includes both advancements in synthetic biology toolkit development and pitfalls in unpredictable fermentation behaviors. To develop a synthetic biology "tool kit" for A. succinogenes, information gleaned from a growth study and antibiotic screening was used to characterize 22 promoters which demonstrated a 260-fold range of fluorescence protein expression. The strongest of the promoters was incorporated into an inducible system for tunable gene control in A. succinogenes using the promoter for the lac operon as a template. This system flaunted a 481-fold range of expression and no significant basal expression. These findings were accompanied by unexpected changes in fermentation products characterized by a loss of succinic acid and increase in lactic acid after approximately 10 months in the lab. During evaluation of the fermentation shifts, new tests of the synthetic biology tools in a succinic acid producing strain revealed a significant loss in their functionality. Contamination and mutation were ruled out as causes and further testing is needed to elucidate the driving factors. The significance of this work is to share a successful tool development strategy that could be employed in other non-model species, report on an unfortunate phenomenon that needs addressed for further development of A. succinogenes, and provide a cautionary tale for those undertaking non-model research. In sharing our findings, we seek to provide tools and necessary information for further development of A. succinogenes as a platform for bioproduction of succinic acid and to illustrate the importance of diligent and long-term observation when working with non-model bacteria.


Assuntos
Actinobacillus/genética , Fermentação , Regulação Bacteriana da Expressão Gênica , Ativação Transcricional , Actinobacillus/metabolismo , Óperon Lac , Ácido Láctico/metabolismo , Regiões Promotoras Genéticas , Ácido Succínico/metabolismo
20.
Health Technol Assess ; 25(6): 1-68, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33511963

RESUMO

BACKGROUND: Cataract surgery is one of the most common operations. Femtosecond laser-assisted cataract surgery (FLACS) is a technique that automates a number of operative steps. OBJECTIVES: To compare FLACS with phacoemulsification cataract surgery (PCS). DESIGN: Multicentre, outcome-masked, randomised controlled non-inferiority trial. SETTING: Three collaborating NHS hospitals. PARTICIPANTS: A total of 785 patients with age-related cataract in one or both eyes were randomised between May 2015 and September 2017. INTERVENTION: FLACS (n = 392 participants) or PCS (n = 393 participants). MAIN OUTCOME MEASURES: The primary outcome was uncorrected distance visual acuity in the study eye after 3 months, expressed as the logarithm of the minimum angle of resolution (logMAR): 0.00 logMAR (or 6/6 if expressed in Snellen) is normal (good visual acuity). Secondary outcomes included corrected distance visual acuity, refractive outcomes (within 0.5 dioptre and 1.0 dioptre of target), safety and patient-reported outcome measures at 3 and 12 months, and resource use. All trial follow-ups were performed by optometrists who were masked to the trial intervention. RESULTS: A total of 353 (90%) participants allocated to the FLACS arm and 317 (81%) participants allocated to the PCS arm attended follow-up at 3 months. The mean uncorrected distance visual acuity was similar in both treatment arms [0.13 logMAR, standard deviation 0.23 logMAR, for FLACS, vs. 0.14 logMAR, standard deviation 0.27 logMAR, for PCS, with a difference of -0.01 logMAR (95% confidence interval -0.05 to 0.03 logMAR; p = 0.63)]. The mean corrected distance visual acuity values were again similar in both treatment arms (-0.01 logMAR, standard deviation 0.19 logMAR FLACS vs. 0.01 logMAR, standard deviation 0.21 logMAR PCS; p = 0.34). There were two posterior capsule tears in the PCS arm. There were no significant differences between the treatment arms for any secondary outcome at 3 months. At 12 months, the mean uncorrected distance visual acuity was 0.14 logMAR (standard deviation 0.22 logMAR) for FLACS and 0.17 logMAR (standard deviation 0.25 logMAR) for PCS, with a difference between the treatment arms of -0.03 logMAR (95% confidence interval -0.06 to 0.01 logMAR; p = 0.17). The mean corrected distance visual acuity was 0.003 logMAR (standard deviation 0.18 logMAR) for FLACS and 0.03 logMAR (standard deviation 0.23 logMAR) for PCS, with a difference of -0.03 logMAR (95% confidence interval -0.06 to 0.01 logMAR; p = 0.11). There were no significant differences between the arms for any other outcomes, with the exception of the mean binocular corrected distance visual acuity with a difference of -0.02 logMAR (95% confidence interval -0.05 to 0.00 logMAR) (p = 0.036), which favoured FLACS. There were no significant differences between the arms for any health, social care or societal costs. For the economic evaluation, the mean cost difference was £167.62 per patient higher for FLACS (95% of iterations between -£14.12 and £341.67) than for PCS. The mean QALY difference (FLACS minus PCS) was 0.001 (95% of iterations between -0.011 and 0.015), which equates to an incremental cost-effectiveness ratio (cost difference divided by QALY difference) of £167,620. LIMITATIONS: Although the measurement of outcomes was carried out by optometrists who were masked to the treatment arm, the participants were not masked. CONCLUSIONS: The evidence suggests that FLACS is not inferior to PCS in terms of vision after 3 months' follow-up, and there were no significant differences in patient-reported health and safety outcomes after 12 months' follow-up. In addition, the statistically significant difference in binocular corrected distance visual acuity was not clinically significant. FLACS is not cost-effective. FUTURE WORK: To explore the possible differences in vision in patients without ocular co-pathology. TRIAL REGISTRATION: Current Controlled Trials ISRCTN77602616. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 6. See the NIHR Journals Library website for further project information. Moorfields Eye Charity (grant references GR000233 and GR000449 for the endothelial cell counter and femtosecond laser used).


Cataract is a condition in which the natural lens inside the eye becomes cloudy, leading to loss of vision. In cataract surgery, the cloudy lens is replaced by a clear, artificial one. The standard surgical method (phacoemulsification) is carried out manually by the surgeon using ultrasound. Part of the procedure can now be automated using a computer-controlled laser. This is called femtosecond laser-assisted cataract surgery (FLACS). The potential advantages of FLACS include greater precision reproducibility, but this new technique is more expensive than the standard surgery. We performed a randomised controlled trial comparing the two techniques. We assessed vision, surgical complications, patient-related quality of life and cost-effectiveness at 3 and 12 months. We found that the outcomes were almost identical for eyesight, quality of life and complications. Overall, the evidence suggests that the new technique is not worth the additional costs.


Assuntos
Extração de Catarata , Catarata , Terapia a Laser , Facoemulsificação , Humanos , Lasers
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