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Peroxyacetyl nitrate (PAN) is a significant indicator of atmospheric photochemical pollution, which can influence the regional distribution of ozone (O3) and hydroxyl radical (OH) through long-range transport. However, investigations of PAN incorporating comprehensive measurement and explicit modeling analysis are limited, hindering complete understandings of its temporal behavior, sources, and impacts on photochemistry. Here we conducted a 1-year continuous observation of PAN and relative atmospheric species in Nanjing located in Yangtze River Delta (YRD). The annual mean concentration of PAN was 0.62 ± 0.49 ppbv and showed a bimodal monthly variation, peaking in April-June and November-January, respectively. This pattern is different from the typical pattern of photochemistry, suggesting important contributions of other non-photochemical processes. We further analyzed the PAN budget using an observation-based model, by which, PAN from local photochemical production and regional source could be decoupled. Our results revealed that local photochemical production of PAN is the sole contributor to PAN in summer, whereas about half of the total PAN concentration is attributed to regional source in winter. Although the formation of PAN can suppress the atmospheric oxidation capacity by consuming the peroxyacetyl radical and nitrogen dioxide (NO2), our analyses suggested this effect is minor at our station (-3.2 ± 1.1 % in summer and - 7.2 ± 2.8 % in winter for O3 formation). However, it has the potential to enhance O3 and OH formation by 14.16 % and 5.93 %, if transported to cleaner environments with air pollutants halved. Overall, our study highlights the importance of both local photochemistry and regional process in PAN budget and provides a useful evaluation on the impact of PAN on atmospheric oxidation capacity.
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This is the protocol for an evidence and gap map. The objectives are as follows: To map available randomized control trials, economic evaluations, and systematic reviews that assess the effectiveness and cost-effectiveness of non-pharmacological interventions for older people with a diagnosis of depression and identify any existing gaps in the evidence that can inform future research.
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A workflow that combined metagenomic sequencing with flow cytometry was developed. The absolute abundance of pathogens was accurately estimated in mock communities and real samples. Metagenome-assembled genomes binned from metagenomic data set is robust in phylogenetic analysis and virulence profiling.
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As the fast development of wearable devices and Internet of things technologies, real-time monitoring of ECG signals is quite critical for cardiovascular diseases. However, dynamic ECG signals recorded in free-living conditions suffered from extremely serious noise pollution. Presently, most algorithms for ECG signal evaluation were designed to divide signals into acceptable and unacceptable. Such classifications were not enough for real-time cardiovascular disease monitoring. In the study, a wearable ECG quality database with 50,085 recordings was built, including A/B/C (or high quality/medium quality/low quality) three quality grades (A: high quality signals can be used for CVD detection; B: slight contaminated signals can be used for heart rate extracting; C: heavily polluted signals need to be abandoned). A new SQA classification method based on a three-layer wavelet scattering network and transfer learning LSTM was proposed in this study, which can extract more systematic and comprehensive characteristics by analyzing the signals thoroughly and deeply. Experimental results ( mACC = 98.56%, mF 1 = 98.55%, Se A = 97.90%, Se B = 98.16%, Se C = 99.60%, + P A = 98.52%, + P B = 97.60%, + P C = 99.54%, F 1A = 98.20%, F 1B = 97.90%, F 1C = 99.60%) and real data validations proved that this proposed method showed the high accuracy, robustness, and computationally efficiency. It has the ability to evaluate the long-term dynamic ECG signal quality. It is advantageous to promoting cardiovascular disease monitoring by removing contaminating signals and selecting high-quality signal segments for further analysis.
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Purpose: The purpose of this study was to investigate the interest in practice ownership among pediatric dentistry residents and influencing factors, particularly educational debt. Methods: An invitation to participate in an anonymous survey was sent to 933 pediatric dentistry residents training in the United States in the spring of 2020. Results: The survey response rate was 32.9 percent. Of the respondents, 61.2 percent reported being extremely or very interested in practice ownership and 49.8 percent anticipated becoming a practice owner within five years of graduation. An inverse relationship was seen between one's level of comfort in assuming a business loan to acquire a practice and having an educational debt burden of $400,000 or greater (P=0.002). Practice management preparation was the most common concern related to future practice ownership. Those feeling completely, very, or moderately prepared to manage a dental practice were over 40 percent more likely to be extremely or very interested in practice ownership than were those who felt slightly or not at all prepared (P<0.001). Conclusions: There appears to be broad interest in practice ownership among pediatric dentistry residents. Relatively high educational debt may negatively influence future practice ownership, but it may be less influential than other factors.
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Intenção , Internato e Residência , Escolha da Profissão , Criança , Humanos , Propriedade , Odontopediatria/educação , Inquéritos e Questionários , Apoio ao Desenvolvimento de Recursos Humanos , Estados UnidosRESUMO
OBJECTIVE: Bacteria in the dental biofilm produceacid after consumption of carbohydrates which if left unmonitored leads to caries formation. We present O-pH, a device that can measure dental biofilm acidity and provide quantitative feedback to assist in oral health monitoring. METHOD: O-pH utilizes a ratiometric pH sensing method by capturing fluorescence of Sodium Fluorescein, an FDA approved chemical dye. The device was calibrated to a lab pH meter using buffered fluorescein solution with a correlation coefficient of 0.97. The calibration was further verified in vitro on additional buffered solution, artificial, and extracted teeth. An in vivo study on 30 pediatric subjects was performed to measure pH before (rest pH) and after (drop pH) a sugar rinse, and the resultant difference in pH (diff pH) was calculated. The study enrolled subjects with low (Post-Cleaning) and heavy (Pre-Cleaning) biofilm load, having both unhealthy/healthy surfaces. Further, we modified point-based O-pH to an image-based device using a multimode-scanning fiber endoscope (mm-SFE) and tested in vivo on one subject. RESULTS AND CONCLUSION: We found significant difference between Post-Cleaning and Pre-Cleaning group using drop pH and diff pH. Additionally, in Pre-Cleaning group, the rest and drop pH is lower at the caries surfaces compared to healthy surfaces. Similar trend was not noticed in the Post-Cleaning group. mm-SFE pH scope recorded image-based pH heatmap of a subject with an average diff pH of 1.5. SIGNIFICANCE: This work builds an optical pH prototype and presents a pioneering study for non-invasively measuring pH of dental biofilm clinically.
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Biofilmes , Esmalte Dentário , Calibragem , Criança , Esmalte Dentário/diagnóstico por imagem , Humanos , Concentração de Íons de HidrogênioRESUMO
INTRODUCTION: Malaria exerts a significant economic burden on health care providers and households and our study attempts to make claims on the cost effectiveness of artesunate against quinine in patients under 14 years of age in Zambia. Also, to find the average total costs involved in the treatment of severe malaria in children and their impact on household expenditure. METHODS: Cost-effectiveness analysis of severe malaria treatment was conducted from a healthcare provider perspective using a Markov model. Standard costing was performed for the identification, measurement and assessment phases with data from quantification reports for anti-malaria commodities as these documents provides drug procurement costs from suppliers and freight costs. Average and incremental cost-effectiveness ratio were estimated and uncertainties were assessed through probabilistic sensitivity analysis. RESULTS: In Zambia severe malaria in children has been shown to account for over 45% of the total monthly curative healthcare costs incurred by households compared to the mean per capita monthly income. The cost of treating severe malaria depleted 7.67% of the monthly average household income. According, to the cost effectiveness analysis the of artesunate with quinine the ICER was $105 per death averted. CONCLUSION: The use of artesunate over quinine in the treatment of severe malaria in children under 14 years is a highly cost-effective strategy for the healthcare provider in Zambia.
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Gaseous sulfuric acid (H2SO4) is a crucial precursor for secondary aerosol formation, particularly for new particle formation (NPF) that plays an essential role in the global number budget of aerosol particles and cloud condensation nuclei. Due to technology challenges, global-wide and long-term measurements of gaseous H2SO4 are currently very challenging. Empirical proxies for H2SO4 have been derived mainly based on short-term intensive campaigns. In this work, we performed comprehensive measurements of H2SO4 and related parameters in the polluted Yangtze River Delta in East China during four seasons and developed a physical proxy based on the budget analysis of gaseous H2SO4. Besides the photo-oxidation of SO2, we found that primary emissions can contribute considerably, particularly at night. Dry deposition has the potential to be a non-negligible sink, in addition to condensation onto particle surfaces. Compared with the empirical proxies, the newly developed physical proxy demonstrates extraordinary stability in all the seasons and has the potential to be widely used to improve the understanding of global NPF fundamentally.
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Poluentes Atmosféricos , Material Particulado , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental , Tamanho da Partícula , Material Particulado/análise , Rios , Ácidos SulfúricosRESUMO
Entrepreneurship plays an important role in the development of national economy. The study aims to accelerate the construction of social and economic structure by improving the success rate of new entrepreneurs in the process of innovation and entrepreneurship. First, the related theories of financial risk prediction are introduced, and entrepreneurial psychological status and the psychological states on entrepreneurship are analyzed. Second, the current situation of entrepreneurial psychology of new entrepreneurs is analyzed through a questionnaire survey and model test. The results show that private enterprises account for the largest proportion, with a percentage of 58.14% of 125. In total, 32 Chinese-foreign joint ventures rank second and account for 14.88% of the total, and the scale of each type of enterprises accounts for 25%, respectively. The operating years of enterprises are mainly between 10 and 20 years. Among the enterprises surveyed, the significant level of entrepreneurial psychology and entrepreneurial opportunity of entrepreneurs is p = 0.000-0.01. It indicates that males' psychological adjustment ability and entrepreneurial ability in the entrepreneurial process are higher than females', and their entrepreneurial psychological states and entrepreneurial ability will improve with the growth of age, education levels, and positions. It is concluded that entrepreneurial psychological capital and entrepreneurial opportunity are significantly positively correlated with financial risk expectation. The research results prove the impact of financial risks on the entrepreneurial psychology of new entrepreneurs, and provide a reference for new entrepreneurs in predicting financial risks.
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BACKGROUND: This study developed a feasible catalytic method for d-allulose syrup production using a fusion enzyme, either in free or immobilized form, through hydrolysis of inulin extracted from Jerusalem artichoke tubers. RESULTS: d-Allulose 3-epimerase (DAE) was actively expressed in secretory form by fusing with the extracellular exo-inulinase CSCA in Escherichia coli BL21 (DE3). The best linker ligating the two enzymes was a flexible peptide containing 12 residues (GSAGSAAGSGEF). At 55 °C and pH 8.0, and as with the addition of 1 mmol L-1 Mn2+ , the CSCA-linkerE-DAE fusion enzyme obtained through high cell-density cultivation displayed a maximal exo-inulinase activity of 21.8 U mg-1 and resulted in a yield of 6.3 g L-1 d-allulose and 39.2 g L-1 d-fructose using 60 g L-1 inulin as the raw material. Catechol-modified alginate with titanium ions (Alg(Ti)PDA) was found to be a promising immobilization material for the fusion enzyme. After conversion for 8 days, the Alg(Ti)PDA-immobilized CSCA-linkerE-DAE (8 U g-1 ) completed 24 reaction cycles and retained over 80% of its original activity. Each reaction obtained an average of 19.8 g L-1 d-allulose and 32.7 g L-1 D-fructose from 60 g L-1 inulin. CONCLUSION: This study shed light on a feasible and cost-effective approach for the production of syrup containing d-allulose and D-fructose with inulin as the raw material via the use of a CSCA and DAE fusion enzyme. This syrup is of added value as a functional sweetener. © 2020 Society of Chemical Industry.
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Frutose/química , Glicosídeo Hidrolases/química , Inulina/química , Racemases e Epimerases/química , Proteínas Recombinantes de Fusão/química , Biocatálise , Enzimas Imobilizadas/química , Enzimas Imobilizadas/genética , Enzimas Imobilizadas/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Tecnologia de Alimentos/economia , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Inulina/genética , Inulina/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismoRESUMO
Retained placentae (RP) results in significant economic losses to dairy farmers. In Experiment 1, to screen biochemical indicators of RP, 21 cows with RP and 21 cows with no retained placenta (NRP) were selected as a control group, and blood was collected at -7 d, 0 h (parturition) and 12 h. Serum biochemical indicators were ascertained. Results indicate serum concentrations of phosphorus (P) and blood urea nitrogen (BUN) in cows of the RP group were markedly greater than in cows of the NRP group at -7 d (P < 0.01). In Experiment 2, to evaluate predictive indicators for RP, 34 cows with RP and 34 cows with NRP were selected, and there was blood sampling at -15 d, -10 d, -7 d, -4 d, and -1 d. Serum P, BUN, and total protein (TP) were evaluated. Associations of values among the three indicators and occurrence of RP were analyzed using binary logistic regression. Results indicate there was a negative correlation between only the values for BUN and RP (P = 0.016). In Experiment 3, to test hypothesis that relatively greater concentrations of BUN effects immune function in placental tissues, four cows were selected, placentae were collected at 0 and 12 h, and hematoxylin-eosin (HE) staining was performed. Results indicated that the extent of inflammatory cell infiltration and vascular proliferation were less at the 12 than 0-hour timepoint. Taken together, BUN at -7 d may serve as a predictive indicator of RP in cows.
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Nitrogênio da Ureia Sanguínea , Doenças dos Bovinos/sangue , Placenta Retida/veterinária , Animais , Biomarcadores/sangue , Estudos de Casos e Controles , Bovinos , Doenças dos Bovinos/diagnóstico , Feminino , Placenta/citologia , Placenta/patologia , Placenta Retida/sangue , Placenta Retida/diagnóstico , GravidezRESUMO
BACKGROUND AND AIM: Additional simethicone (SIM) can improve adequate bowel preparation and adenoma detection rate (ADR). However, there is no consensus on the optimal dose of SIM. In this study, we compared the adequate bowel preparation rate with supplementation of split-dose 2 L polyethylene glycol (PEG) with low-dose SIM (200 mg) versus high-dose SIM (1200 mg). METHODS: This was a prospective, randomized, observer-blinded trial involving consecutive subjects undergoing colonoscopy. The primary outcome was adequate bowel preparation as assessed by Boston Bowel Preparation Scale (BBPS) score. RESULTS: Four hundred subjects were randomly allocated to low-dose SIM or high-dose SIM group. Baseline characteristics were comparable in the two groups (P > 0.05). No significant between-group differences were observed with respect to total bubble scale (BS) (8.49 ± 1.00 vs 8.39 ± 1.10, P = 0.07), total BBPS score (8.70 ± 0.81 vs 8.29 ± 1.18, P = 0.98), ADR (33.68% vs 31.79%, P = 0.69) or withdrawal time (13 [range, 10-16] min vs 13 [10-15] min, P = 0.96). The intubation time in low-dose SIM group was significantly shorter than that in high-dose SIM group (8 (4-16) min vs 10 [6-17] min, P = 0.04). In addition, BS scores as well as diminutive ADR in right colon were superior in the low-dose SIM group (2.68 ± 0.59 vs 2.52 ± 0.73, P = 0.03 and 54.29% vs 30.30%, P = 0.046, respectively). CONCLUSION: Addition of low-dose SIM to split-dose 2 L PEG was as effective as addition of high-dose SIM with respect to adequate bowel preparation, ADR and patient tolerance. However, low-dose SIM was superior with respect to intubation time, right colon BS scores, right colon diminutive ADR and cost savings.
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Catárticos/administração & dosagem , Colonoscopia/métodos , Polietilenoglicóis/administração & dosagem , Simeticone/administração & dosagem , Adenoma/diagnóstico , Adulto , Catárticos/química , Colonoscopia/economia , Neoplasias Colorretais/diagnóstico , Redução de Custos , Tolerância a Medicamentos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Tempo , Resultado do TratamentoRESUMO
A safe, efficient, environmentally friendly process for producing isomaltulose is needed. Here, the biocatalyst, sucrose isomerase (SIase) from Erwinia rhapontici NX-5, displayed on the surface of Bacillus subtilis 168 spores (food-grade strain) was applied for isomaltulose production. The anchored SIase showed relatively high bioactivity, suggesting that the surface display system using CotX as the anchoring protein was successful. The stability of the anchored SIase was also significantly better. Thermal stability analysis showed that 80% of relative activity was retained after incubation at 40 °C and 45 °C for 60 min. To develop an economical industrial fermentation medium, untreated beet molasses (30 g/L) and cold-pressed soybean powder (50 g/L) were utilised as the main broth components for SIase pilot-scale production. Under the optimal conditions, the productive spores converted 92% of sucrose after 6 h and the conversion rate was 45% after six cycles. Isomaltulose production with this system using the agricultural residues, untreated beet molasses and soybean powder, as substrates is cost-effective and environmentally friendly and can help to overcome issues due to the genetic background.
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Bacillus subtilis/enzimologia , Erwinia/enzimologia , Proteínas Fúngicas/química , Glucosiltransferases/química , Isomaltose/análogos & derivados , Esporos Bacterianos/enzimologia , Bacillus subtilis/genética , Erwinia/genética , Proteínas Fúngicas/genética , Glucosiltransferases/genética , Temperatura Alta , Isomaltose/síntese química , Isomaltose/química , Isomaltose/genética , Esporos Bacterianos/genética , Sacarose/químicaRESUMO
Facile carbocation-initiated [4+2] cycloaddition of o-anisole-substituted propargyl silyl ethers and ynamides led to the formation of 4-vinylcoumarins. Subsequent intramolecular cyclization of 3-aryl-4-vinylcoumarins afforded polycyclic coumarin derivatives 11,12-dihydronaphtho[1,2-c]chromen-5-ones in excellent yields under mild photo-irradiated conditions established by fluorescence analysis-oriented screening.
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OBJECTIVE: In this longitudinal pilot study, we aimed to investigate the intra-, interobserver, and scan-rescan reproducibility of marrow fat fraction (FF) measurements using three-point Dixon imaging in osteoporotic rabbits: comparison with histopathology. METHODS: Twenty female rabbits were randomly assigned to sham-operation and ovariectomy in combination with daily methylprednisolone hemisuccinate groups (nâ=â10 per group). Marrow FF by three-point Dixon technique and bone density by dual-energy x-ray absorptiometry were assessed at baseline, 6 and 12 weeks after operation. Intra-, inter-reader, and scan-rescan reliability of FF measurements were evaluated using intraclass correlation coefficient (ICC) and Bland-Altman 95% limit of agreement. Histomorphometry was performed to quantify marrow adipocyte parameters. RESULTS: Intra- and inter-reader reproducibility of FF measurements was "substantial" (ICCâ=â0.984 and 0.978, respectively). Although the ICC for scan-rescan reliability was excellent (ICCâ=â0.962), increased measurement variability was observed using Bland-Altman plot. Relative to the sham-operated rabbits, the adipocytes mean diameter, density, and percent adipocytes area in the osteoporotic rabbits increased by 23.4%, 68.9%, and 117.0%, respectively. Marrow FF was positively correlated with the quantitative parameters of adipocytes, particularly with percent adipocyte area, but inversely associated with bone density. At the relatively early stage, the percentage of bone loss was similar to that of elevated fatty marrow in the osteoporotic rabbits; at the later stage, the change for the latter outweighed that of the former. CONCLUSIONS: Results of three-point Dixon technique demonstrated a very reproducible manner within and between observers and acceptable scan-rescan performance in the assessment of marrow fat in rabbits.
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Adiposidade , Densidade Óssea/fisiologia , Medula Óssea/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Osteoporose/diagnóstico por imagem , Absorciometria de Fóton , Adipócitos , Animais , Medula Óssea/fisiopatologia , Feminino , Estudos Longitudinais , Variações Dependentes do Observador , Osteoporose/fisiopatologia , Ovariectomia/efeitos adversos , Projetos Piloto , Coelhos , Distribuição Aleatória , Reprodutibilidade dos TestesRESUMO
BACKGROUND: At the present time, the government is considering to establish the independent financing system for essential medicines (EMs). However, it is still in the exploration phase. The objectives of this study were to calculate and estimate financing amount of EMs in China in 2014 and to provide data evidence for establishing financing mechanism of EMs. METHODS: Two approaches were adopted in this study. First, we used a retrospective research to estimate the cost of EMs in China in 2014. We identified all the 520 drugs listed in the latest national EMs list (2012) and calculated the total sales amount of these drugs in 2014. The other approach included the steps that first selecting the 109 most common diseases in China, then identifying the EMs used to treat them, and finally estimating the total cost of these drugs. RESULTS: The results of the two methods, which showed the estimated financing amounts of EMs in China in 2014, were 17,776.44 million USD and 19,094.09 million USD, respectively. CONCLUSIONS: Comparing these two results, we concluded that the annual budget needed to provide for the EMs in China would be about 20 billion USD. Our study also indicated that the irrational drug use continued to plague the health system with intravenous fluids and antibiotics being the typical examples, as observed in other studies.
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Medicamentos Essenciais/economia , China , Humanos , Estudos Retrospectivos , Fatores de TempoRESUMO
MOTIVATION: Advances in chromosome conformation capture and next-generation sequencing technologies are enabling genome-wide investigation of dynamic chromatin interactions. For example, Hi-C experiments generate genome-wide contact frequencies between pairs of loci by sequencing DNA segments ligated from loci in close spatial proximity. One essential task in such studies is peak calling, that is, detecting non-random interactions between loci from the two-dimensional contact frequency matrix. Successful fulfillment of this task has many important implications including identifying long-range interactions that assist interpreting a sizable fraction of the results from genome-wide association studies. The task - distinguishing biologically meaningful chromatin interactions from massive numbers of random interactions - poses great challenges both statistically and computationally. Model-based methods to address this challenge are still lacking. In particular, no statistical model exists that takes the underlying dependency structure into consideration. RESULTS: In this paper, we propose a hidden Markov random field (HMRF) based Bayesian method to rigorously model interaction probabilities in the two-dimensional space based on the contact frequency matrix. By borrowing information from neighboring loci pairs, our method demonstrates superior reproducibility and statistical power in both simulation studies and real data analysis. AVAILABILITY AND IMPLEMENTATION: The Source codes can be downloaded at: http://www.unc.edu/â¼yunmli/HMRFBayesHiC CONTACT: ming.hu@nyumc.org or yunli@med.unc.edu SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
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Cromossomos , Teorema de Bayes , Estudo de Associação Genômica Ampla , Cadeias de Markov , Reprodutibilidade dos TestesRESUMO
Lignocellulosic biomass has been identified as an economic and environmental feedstock for future biotechnological production. Here, for the first time, poly-(γ-glutamic acid) (PGA) production by Bacillus subtilis NX-2 using rice straw is investigated. Based on two-stage hydrolysis and characteristic consumption of xylose and glucose by B. subtilis NX-2, a co-fermentation strategy was designed to better accumulate PGA in a 7.5L fermentor by two feeding methods. The maximum cumulative respective PGA production and PGA productivity were 73.0 ± 0.5 g L(-1) and 0.81 g L(-1) h(-1) by the continuous feeding method, with carbon source cost was saved by 84.2% and 42.5% compared with glucose and cane molasse, respectively. These results suggest that rice straw, a type of abundant, low-cost, non-food lignocellulosic feedstock, may be feasibly and efficiently utilized for industrial-scale production of PGA.
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Bacillus subtilis/metabolismo , Biotecnologia/métodos , Oryza/metabolismo , Ácido Poliglutâmico/biossíntese , Resíduos , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/crescimento & desenvolvimento , Biotecnologia/economia , Carbono/farmacologia , Fermentação/efeitos dos fármacos , Glucose/farmacologia , Hidrólise , Oryza/efeitos dos fármacos , Fatores de Tempo , Xilose/farmacologiaRESUMO
This study tended to apply biorefinery of indigenous microbes to the fermentation of target-product generation through a novel control strategy. A novel strategy for co-producing two valuable homopoly(amino acid)s, poly(ε-l-lysine) (ε-PL) and poly(l-diaminopropionic acid) (PDAP), was developed by controlling pH and dissolved oxygen concentrations in Streptomyces albulus PD-1 fermentation. The production of ε-PL and PDAP got 29.4 and 9.6gL(-1), respectively, via fed-batch cultivation in a 5L bioreactor. What is more, the highest production yield (21.8%) of similar production systems was achieved by using this novel strategy. To consider the economic-feasibility, large-scale production in a 1t fermentor was also implemented, which would increase the gross profit of 54,243.5USD from one fed-batch bioprocess. This type of fermentation, which produces multiple commercial products from a unified process is attractive, because it will improve the utilization rate of raw materials, enhance production value and enrich product variety.
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Reatores Biológicos/economia , Polilisina/economia , Polilisina/metabolismo , Streptomyces/metabolismo , beta-Alanina/análogos & derivados , Análise da Demanda Biológica de Oxigênio/economia , Análise da Demanda Biológica de Oxigênio/métodos , Reatores Biológicos/microbiologia , China , Simulação por Computador , Glucose/economia , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Renda , Modelos Econômicos , Oxigênio/economia , Oxigênio/metabolismo , beta-Alanina/economia , beta-Alanina/metabolismoRESUMO
Poly(γ-glutamic acid) (γ-PGA) production by Bacillus subtilis NX-2 was carried out through solid-state fermentation with dry mushroom residues (DMR) and monosodium glutamate production residues (MGPR; a substitute of glutamate) for the first time. Dry shiitake mushroom residue (DSMR) was found to be the most suitable solid substrate among these DMRs; the optimal DSMR-to-MGPR ratio was optimized as 12:8. To increase γ-PGA production, industrial waste glycerol was added as a carbon source supplement to the solid-state medium. As a result, γ-PGA production increased by 34.8%. The batch fermentation obtained an outcome of 115.6 g kg(-1) γ-PGA and 39.5×10(8) colony forming units g(-1) cells. Furthermore, a satisfactory yield of 107.7 g kg(-1) γ-PGA was achieved by compost experiment on a scale of 50 kg in open air, indicating that economically large-scale γ-PGA production was feasible. Therefore, this study provided a novel method to produce γ-PGA from abundant and low-cost agroindustrial residues.