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1.
J Hazard Mater ; 388: 122070, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31954307

RESUMO

The emerging antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are increasingly appreciated to be as important as microbial contaminants. This paper focused on UV-activated persulfate (UV/PS), an advanced oxidation process, in removing ARB and ARGs from secondary wastewater effluent. Results showed that the inactivation efficiency of macrolides-resistant bacteria (MRB), sulfonamides-resistant bacteria (SRB), tetracyclines-resistant bacteria (TRB) and quinolones-resistant bacteria (QRB) by UV/PS reached 96.6 %, 94.7 %, 98.0 % and 99.9 % in 10 min, respectively. UV/PS also showed significant removal efficiency on ARGs. The reduction of total ARGs reached 3.84 orders of magnitude in UV/PS which is more than that in UV by 0.56 log. Particularly, the removal of mobile genetic elements (MGE) which might favor the horizontal gene transfer of ARGs among different microbial achieved 76.09 % by UV/PS. High-throughput sequencing revealed that UV/PS changed the microbial community. The proportions of Proteobacteria and Actinobacteria that pose human health risks were 4.25 % and 1.6 % less than UV, respectively. Co-occurrence analyzes indicated that ARGs were differentially contributed by bacterial taxa. In UV/PS system, hydroxyl radical and sulfate radical contributed to the removal of bacteria and ARGs. Our study provided a new method of UV/PS to remove ARGs and ARB for wastewater treatment.

2.
Bioresour Technol ; 297: 122505, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31806513

RESUMO

This study presents a novel approach based on addition of biochar generated from residue of cornstalk left after pretreatment and hydrolysis (RCPH-biochar) to improve hydrogen production from cornstalk hydrolysate. RCPH-biochar at concentration of 15 g L-1 substantially enhanced hydrogen generation during batch tests, with the highest cumulative hydrogen volume (3990 mL L-1) being 1.7 times that without RCPH-biochar. Then, continuous hydrogen production performance demonstrated that RCPH-biochar was capable of retaining biomass in the reactor, at 6 h hydraulic retention time, hydrogen production rate (22.8 mmol H2 L-1 h-1) was tripled compared to the control, meanwhile, glucose and xylose utilization reached to 82.3% and 54.6%, respectively. Overall material balance indicates continuous hydrogen production with RCPH-biochar enabled 63.4% higher cornstalk transfer to H2 and 53.3% more cornstalk utilization. The findings reported is a closed-loop process and is economically and environmentally attractive, which might support comprehensive cornstalk utilization with less energy input in the future.


Assuntos
Hidrogênio , Anaerobiose , Carvão Vegetal , Estudos de Viabilidade , Fermentação
3.
Chemosphere ; 234: 893-901, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31252361

RESUMO

Biological phosphorus removal (BPR) is an economical and sustainable processes for the removal of phosphorus (P) from wastewater, achieved by recirculating activated sludge through anaerobic and aerobic (An/Ae) processes. However, few studies have systematically analyzed the optimal hydraulic retention times (HRTs) in anaerobic and aerobic reactions, or whether these are the most appropriate control strategies. In this study, a novel optimization methodology using an improved Q-learning (QL) algorithm was developed, to optimize An/Ae HRTs in a BPR system. A framework for QL-based BPR control strategies was established and the improved Q function, Qt+1(st,st+1)=Qt(st,st+1)+k·[R(st,st+1)+γ·maxatQt(st,st+1)-Qt(st,st+1)] was derived. Based on the improved Q function and the state transition matrices obtained under different HRT step-lengths, the optimum combinations of HRTs in An/Ae processes in any BPR system could be obtained, in terms of the ordered pair combinations of the . Model verification was performed by applying six different influent chemical oxygen demand (COD) concentrations, varying from 150 to 600 mg L-1 and influent P concentrations, varying from 12 to 30 mg L-1. Superior and stable effluent qualities were observed with the optimal control strategies. This indicates that the proposed novel QL-based BPR model performed properly and the derived Q functions successfully realized real-time modelling, with stable optimal control strategies under fluctuant influent loads during wastewater treatment processes.


Assuntos
Algoritmos , Aprendizado de Máquina , Fósforo/isolamento & purificação , Esgotos/microbiologia , Águas Residuárias/química , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos , Metabolismo , Modelos Biológicos , Modelos Teóricos , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/isolamento & purificação
4.
Bioresour Technol ; 243: 548-555, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28697457

RESUMO

Mycelia pellets were employed as biological carrier in a continuous stirred tank reactor to reduce biomass washout and enhance hydrogen production from cornstalk hydrolysate. Hydraulic retention time (HRT) and influent substrate concentration played critical roles on hydrogen production of the bioreactor. The maximum hydrogen production rate of 14.2mmol H2L-1h-1 was obtained at optimized HRT of 6h and influent concentration of 20g/L, 2.6 times higher than the counterpart without mycelia pellets. With excellent immobilization ability, biomass accumulated in the reactor and reached 1.6g/L under the optimum conditions. Upon further energy conversion analysis, continuous hydrogen production with mycelia pellets gave the maximum energy conversion efficiency of 17.8%. These results indicate mycelia pellet is an ideal biological carrier to improve biomass retention capacity of the reactor and enhance hydrogen recovery efficiency from lignocellulosic biomass, and meanwhile provides a new direction for economic and efficient hydrogen production process.


Assuntos
Reatores Biológicos , Hidrogênio , Bactérias , Bactérias Anaeróbias , Fermentação
5.
Bioresour Technol ; 215: 92-99, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27090403

RESUMO

With the increasing energy crisis and rising concern over climate change, the development of clean alternative energy sources is of great importance. Biohydrogen produced from lignocellulosic biomass is a promising candidate, because of its positives such as readily available, no harmful emissions, environment friendly, efficient, and renewable. However, obstacles still exist to enable the commercialization of biological hydrogen production from lignocellulosic biomass. Thus the objective of this work is to provide update information about the recent progress on lignocellulosic hydrogen conversion via dark fermentation. In this review, the most important technologies associated with lignocellulosic hydrogen fermentation were covered. Firstly, pretreatment methods for better utilization of lignocellulosic biomass are presented, at the same time, hydrolysis methods assisting to achieve efficient hydrogen fermentation were discussed. Afterwards, issues related to bioprocesses for hydrogen production purposes were presented. Additionally, the paper gave challenges and new insights of lignocellulosic biohydrogen production.


Assuntos
Biomassa , Hidrogênio/química , Lignina/metabolismo , Biotransformação , Fermentação , Hidrólise , Lignina/química
6.
Biotechnol Biofuels ; 7: 82, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24920960

RESUMO

BACKGROUND: Consolidated bioprocessing (CBP) of lignocellulosic biomass to hydrogen offers great potential for lower cost and higher efficiency compared to processes featuring dedicated cellulase production. Current studies on CBP-based hydrogen production mainly focus on using the thermophilic cellulolytic bacterium Clostridium thermocellum and the extremely thermophilic cellulolytic bacterium Caldicellulosiruptor saccharolyticus. However, no studies have demonstrated that the strains in the genus Thermoanaerobacterium could be used as the sole microorganism to accomplish both cellulose degradation and H2 generation. RESULTS: We have specifically screened for moderately thermophilic cellulolytic bacteria enabling to produce hydrogen directly from conversion of lignocellulosic materials. Three new strains of thermophilic cellulolytic bacteria in the genus Thermoanaerobacterium growing at a temperature of 60°C were isolated. All of them grew well on various plant polymers including microcrystalline cellulose, filter paper, xylan, glucose, and xylose. In particular, the isolated bacterium, designated as Thermoanaerobacterium thermosaccharolyticum M18, showed high cellulolytic activity and a high yield of H2. When it was grown in 0.5% microcrystalline cellulose, approximately 82% cellulose was consumed, and the H2 yield and maximum production rate reached 10.86 mmol/g Avicel and 2.05 mmol/L/h, respectively. Natural lignocellulosic materials without any physicochemical or biological pretreatment also supported appreciable growth of strain M18, which resulted in 56.07% to 62.71% of insoluble cellulose and hemicellulose polymer degradation in corn cob, corn stalk, and wheat straw with a yield of 3.23 to 3.48 mmol H2/g substrate and an average production rate of 0.10 to 0.13 mmol H2/L/h. CONCLUSIONS: The newly isolated strain T. thermosaccharolyticum M18 displayed effective degradation of lignocellulose and produced large amounts of hydrogen. This is the first report of a Thermoanaerobacterium species presenting cellulolytic characteristics, and this species thus represents a novel cellulolytic bacterium distinguished from all other known cellulolytic bacteria. In comparison, the extraordinary yield and specific rate of hydrogen for strain M18 obtained from lignocellulose make it more attractive in monoculture fermentation. T. thermosaccharolyticum M18 is thus a potential candidate for rapid conversion of lignocellulose to biohydrogen in a single step.

7.
Mol Biol Rep ; 41(4): 2657-66, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24469718

RESUMO

To explore whether the nonvirus encoded protein could be embedded into Bombyx mori cypovirus (BmCPV) polyhedra. The stable transformants of BmN cells expressing a polyhedrin (Polh) gene of BmCPV were constructed by transfection with a non-transposon derived vector containing a polh gene. The polyhedra were purified from the midguts of BmCPV-infected silkworms and the transformed BmN cells, respectively. The proteins embedded into polyhedra were determined by mass spectrometry analysis. Host derived proteins were detected in the purified polyhedra. Analysis of structure and hydrophilicity of embedded proteins indicated that the hydrophilic proteins, in structure, were similar to the left-handed structure of polyhedrin or the N-terminal domain of BmCPV structural protein VP3, which were easily embedded into the BmCPV polyhedra. The lysate of polyhedra purified from the infected transformation of BmN cells with modified B. mori baculovirus BmPAK6 could infect BmN cells, indicating that B. mori baculovirus could be embedded into BmCPV polyhedra. Both the purified polyhedra and its lysate could be coloured by X-gal, indicating that the ß-galactosidase expressed by BmPAK6 could be incorporated into BmCPV polyhedra. These results suggested that some heterologous proteins and baculovirus could be embedded into polyhedra in an unknown manner.


Assuntos
Bombyx/virologia , Reoviridae/fisiologia , Proteínas Estruturais Virais/metabolismo , Animais , Baculoviridae/genética , Baculoviridae/metabolismo , Linhagem Celular , Interações Hospedeiro-Patógeno , Modelos Moleculares , Conformação Proteica , Proteínas/química , Proteínas/genética , Proteínas/metabolismo , Proteínas Estruturais Virais/química , Montagem de Vírus , beta-Galactosidase/genética , beta-Galactosidase/metabolismo
8.
Biotechnol Biofuels ; 7(1): 178, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25648837

RESUMO

BACKGROUND: Biological hydrogen production from lignocellulosic biomass shows great potential as a promising alternative to conventional hydrogen production methods, such as electrolysis of water and coal gasification. Currently, most researches on biohydrogen production from lignocellulose concentrate on consolidated bioprocessing, which has the advantages of simpler operation and lower cost over processes featuring dedicated cellulase production. However, the recalcitrance of the lignin structure induces a low cellulase activity, making the carbohydrates in the hetero-matrix more unapproachable. Pretreatment of lignocellulosic biomass is consequently an extremely important step in the commercialization of biohydrogen, and for massive realization of lignocellulosic biomass as alternative fuel feedstock. Thus, development of a pretreatment method which is cost efficient, environmentally benign, and highly efficient for enhanced consolidated bioprocessing of lignocellulosic biomass to hydrogen is essential. RESULTS: In this research, fungal pretreatment was adopted for enhanced hydrogen production by consolidated bioprocessing performance. To confirm the fungal pretreatment efficiency, two typical thermochemical pretreatments were also compared side by side. Results showed that the fungal pretreatment was superior to the other pretreatments in terms of high lignin reduction of up to 35.3% with least holocellulose loss (the value was only 9.5%). Microscopic structure observation combined with Fourier transform infrared spectroscopy (FTIR) analysis further demonstrated that the lignin and crystallinity of lignocellulose were decreased with better holocellulose reservation. Upon fungal pretreatment, the hydrogen yield and hydrogen production rate were 6.8 mmol H2 g(-1) pretreated substrate and 0.89 mmol L(-1) h(-1), respectively, which were 2.9 and 4 times higher than the values obtained for the untreated sample. CONCLUSIONS: Results revealed that although all pretreatments could contribute to the enhancement of hydrogen production from cornstalk, fungal pretreatment proved to be the optimal method. It is apparent that besides high hydrogen production efficiency, fungal pretreatment also offered several advantages over other pretreatments such as being environmentally benign and energy efficient. This pretreatment method thus has great potential for application in consolidated bioprocessing performance of hydrogen production.

9.
Amino Acids ; 45(5): 1231-41, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24005483

RESUMO

Proteomic profiles from the wing discs of silkworms at the larval, pupal, and adult moth stages were determined using shotgun proteomics and MS sequencing. We identified 241, 218, and 223 proteins from the larval, pupal, and adult moth stages, respectively, of which 139 were shared by all three stages. In addition, there were 55, 37, and 43 specific proteins identified at the larval, pupal, and adult moth stages, respectively. More metabolic enzymes were identified among the specific proteins expressed in the wing disc of larvae compared with pupae and moths. The identification of FKBP45 and the chitinase-like protein EN03 as two proteins solely expressed at the larval stage indicate these two proteins may be involved in the immunological functions of larvae. The myosin heavy chain was identified in the pupal wing disc, suggesting its involvement in the formation of wing muscle. Some proteins, such as proteasome alpha 3 subunits and ribosomal proteins, specifically identified from the moth stage may be involved in the degradation of old cuticle proteins and new cuticle protein synthesis. Gene ontology analysis of proteins specific to each of these three stages enabled their association with cellular component, molecular function, and biological process categories. The analysis of similarities and differences in these identified proteins will greatly further our understanding of wing disc development in silkworm and other insects.


Assuntos
Bombyx/genética , Proteínas de Insetos/genética , Metamorfose Biológica , Asas de Animais/crescimento & desenvolvimento , Animais , Bombyx/crescimento & desenvolvimento , Bombyx/metabolismo , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Espectrometria de Massas , Proteômica , Asas de Animais/química , Asas de Animais/metabolismo
10.
Bioresour Technol ; 145: 103-7, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23489570

RESUMO

In this research, environmentally friendly fungal pretreatment was first adopted for deconstruction of cornstalk. Then the fungal-pretreated cornstalk was employed to produce hydrogen in simultaneous saccharification and fermentation (SSF) using crude enzyme from Trichoderma viride and Thermoanaerobacterium thermosaccharolyticum W16. The influence of various factors including substrate concentration, initial pH, and enzyme loading on hydrogen production were evaluated. The highest hydrogen yield of 89.3 ml/g-cornstalk was obtained with an initial pH 6.5, 0.75% substrate concentration, and 34 FPU/g cellulose. Compared the result with SSF of physical or chemical pretreated lignocellulosic materials, this research suggested an economic and efficient way for hydrogen production from lignocellulosic biomass.


Assuntos
Reatores Biológicos , Celulases/metabolismo , Hidrogênio/metabolismo , Lignina/metabolismo , Caules de Planta/química , Thermoanaerobacterium/metabolismo , Zea mays/química , Fermentação , Hidrogênio/isolamento & purificação , Hidrólise , Trichoderma/enzimologia
11.
Bioresour Technol ; 124: 347-54, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22995165

RESUMO

This paper offers an effective pretreatment method that can simultaneously achieve excess sludge reduction and bio-hydrogen production from sludge self-fermentation. Batch tests demonstrated that the combinative use of ozone/ultrasound pretreatment had an advantage over the individual ozone and ultrasound pretreatments. The optimal condition (ozone dose of 0.158 g O(3)/g DS and ultrasound energy density of 1.423 W/mL) was recommended by response surface methodology. The maximum hydrogen yield was achieved at 9.28 mL H(2)/g DS under the optimal condition. According to the kinetic analysis, the highest hydrogen production rate (1.84 mL/h) was also obtained using combined pretreatment, which well fitted the predicted equation (the squared regression statistic was 0.9969). The disintegration degrees (DD) were limited to 19.57% and 46.10% in individual ozone and ultrasound pretreatments, while it reached up to 60.88% in combined pretreatment. The combined ozone/ultrasound pretreatment provides an ideal and environmental friendly solution to the problem of sludge disposal.


Assuntos
Hidrogênio/metabolismo , Ozônio/química , Esgotos , Ultrassom
12.
Bioresour Technol ; 114: 365-9, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22516249

RESUMO

The feasibility of fungal pretreatment of cornstalk with Phanerochaete chrysosporium for enzymatic saccharification and H(2) production was investigated in this study. Firstly, cornstalk was pretreated with P. chrysosporium at 29 °C under static condition for 15 d, lignin reduction was up to 34.3% with holocellulose loss less than 10%. Microscopic structure observation combined FTIR analysis further demonstrated that the lignin and crystallinity were decreased. Subsequently, the fungal-pretreated cornstalk was subjected to enzymatic hydrolysis by the crude cellulase from Trichoderma viride to produce fermentable sugars which were then fermented to bio-H(2) using Thermoanaerobacterium thermosaccharolyticum W16. The maximum enzymatic saccharification was found to be 47.3% which was 20.3% higher than the control without pretreatment. Upon fermentation of enzymatic hydrolysate, the yield of H(2) was calculated to be 80.3 ml/g-pretreated cornstalk. The present results suggested the potential of using hydrogen-producing bacteria for high-yield conversion of cornstalk into bio-H(2) integrate with biological pretreatment and enzymatic saccharification.


Assuntos
Metabolismo dos Carboidratos/fisiologia , Hidrogênio/isolamento & purificação , Hidrogênio/metabolismo , Resíduos Industriais/prevenção & controle , Phanerochaete/metabolismo , Componentes Aéreos da Planta/microbiologia , Zea mays/microbiologia
13.
J Agric Food Chem ; 60(12): 3173-9, 2012 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-22429285

RESUMO

The pupal stage of the silkworm Bombyx mori Linnaeus lasts for approximately two weeks. However, prolongation of pupal duration would reduce the labor required to process and dry fresh cocoons. This study investigated the effects of BmKIT(3)(R) gene (from the Chinese scorpion Buthus martensii Karsch) transfer on the pupal development of B. mori using a Gal4/UAS binary transgenic system. Gal4 driven by a pupa-specific promoter BmWCP4 (from a B. mori wing-cuticle protein gene) or PDP (from a B. mori cocoonase gene), and BmKIT(3)(R) driven by a UAS cis-acting element were used to construct novel piggyBac-derived plasmids containing a neomycin-resistance gene (neo) controlled by the Bombyx mori nucleopolyhedrovirus (BmNPV) ie-1 (immediate-early gene) promoter and a green fluorescent protein gene (gfp) under the control of the B. mori actin 3 (A3) promoter. The vector was transferred into silkworm eggs by sperm-mediated gene transfer. Transgenic silkworms were produced after screening for neo and gfp genes, and gene transfer was verified by polymerase chain reaction and dot-blot hybridization. The larval development of the hybrid progeny of Gal4- and UAS-transgenic silkworms was similar to that of normal silkworms, but some pupae failed to metamorphose into moths, and the development of surviving pupae was arrested as a result of BmKIT(3)(R) expression. Moreover, Gal4 driven by the BmWCP4 promoter delayed pupal development more effectively than that driven by the PDP promoter in the Gal4/UAS binary transgenic system. Pupal durations of hybrid transgenic silkworm progeny with BmWCP4 and PDP promoters were approximately 5, 2, and 4 days longer, respectively, compared to corresponding normal silkworms, BmWCP4/Gal4, and UAS/BmKIT(3)(R) transgenic silkworms, respectively. These results suggest new avenues of research for prolonging the pupal duration of silkworms.


Assuntos
Animais Geneticamente Modificados/crescimento & desenvolvimento , Bombyx/crescimento & desenvolvimento , Pupa/crescimento & desenvolvimento , Venenos de Escorpião/genética , Animais , Animais Geneticamente Modificados/metabolismo , Bombyx/metabolismo , Proteínas de Ligação a DNA/genética , Expressão Gênica , Técnicas de Transferência de Genes , Vetores Genéticos , Proteínas de Fluorescência Verde/genética , Pupa/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Fatores de Transcrição/genética
14.
Adv Biochem Eng Biotechnol ; 128: 143-63, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22089826

RESUMO

Significant progress has been achieved in China for biohydrogen production from organic wastes, particularly wastewater and agricultural residues, which are abundantly available in China. This progress is reviewed with a focus on hydrogen-producing bacteria, fermentation processes, and bioreactor configurations. Although dark fermentation is more efficient for hydrogen production, by-products generated during the fermentation not only compromise hydrogen production yield but also inhibit the bacteria. Two strategies, combination of dark fermentation and photofermentation and coupling of dark fermentation with a microbial electrolysis cell, are expected to address this issue and improve hydrogen production as well as substrate utilization, which are also discussed. Finally, challenges and perspectives for biohydrogen production are highlighted.


Assuntos
Bactérias Anaeróbias/metabolismo , Reatores Biológicos/microbiologia , Hidrogênio/metabolismo , Esgotos/microbiologia , China , Fermentação
15.
Mol Biol Rep ; 37(6): 2599-608, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19728146

RESUMO

The complete nucleotide sequence of the mitogenome of Bombyx mandarina strain Qingzhou was determined. The circular genome is 15,717 bp long and has the typical gene organization and order of lepidopteran mitogenomes. All protein-coding sequences are initiated with a typical ATN codon, except the COI gene, which has a 4-bp TTAG putative initiator codon. Eleven of the 13 protein-coding gene have a complete termination codon (all TAA), but the remaining two genes terminate with incomplete codons. All transfer RNAs (tRNAs) have a clover-leaf structure typical of the mitochondrial tRNAs, and some of them have a mismatch in the four-stem-and-loop structure. The length of the A + T rich region of B. mandarina strain Qingzhou is 495 bp, shorter than that of B. mandarina strain Tsukuba (747 bp) but similar to that of Bombyx mori. Phylogenetic analysis based on the whole mitochondrial genome sequences of the available sequenced species (B. mori strains C-108, Aojuku, Backokjam, and Xiafang, B. mandarina strains Tsukuba, Ankang, and Qingzhou, and Antheraea pernyi) shows the origin of the domesticated silkmoth B. mori to be the Chinese B. mandarina. Nuclear mitochondrial pseudogene sequences were detected in the nuclear genome of B. mori with the MEGA BLAST search program. A phylogenetic analysis of these nuclear mitochondrial pseudogene sequences suggests that B. mori was domesticated independently in different areas and periods.


Assuntos
Bombyx/genética , Genoma Mitocondrial/genética , Filogenia , Sequência Rica em At/genética , Animais , Sequência de Bases , Núcleo Celular/genética , DNA Mitocondrial/genética , Evolução Molecular , Genes de Insetos/genética , Dados de Sequência Molecular , Fases de Leitura Aberta/genética , Pseudogenes/genética , RNA Ribossômico/genética , RNA de Transferência/genética , Seda/biossíntese , Fatores de Tempo
16.
Bioresour Technol ; 101(6): 2053-8, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19963370

RESUMO

The optimization of culture condition for enhanced hydrogen production by Thermoanaerobacterium thermosaccharolyticum W16 was conducted using statistical experimental design and analysis. Plackett-Burman design was first used to screen the most important variables influencing hydrogen production, and subsequently central composite design was adopted to investigate the optimum value of the selected factors for achieving maximum hydrogen yield. Experimental results showed that xylose, phosphate buffer, and yeast extract had significant influence on hydrogen production and the maximum hydrogen yield of 2.39 mol/mol xylose was predicted when the concentrations of xylose, phosphate buffer, and yeast extract were 12.24 g/L, 0.170 M, and 4.11 g/L, respectively. The results were further verified by repeated experiments under optimal conditions. The excellent correlation between predicted and measured values further confirmed the validity and practicability of this statistical optimum strategy.


Assuntos
Biotecnologia/métodos , Meios de Cultura/química , Fontes Geradoras de Energia , Hidrogênio/química , Microbiologia Industrial/métodos , Thermoanaerobacterium/metabolismo , Tampões (Química) , Células Cultivadas , Técnicas de Química Analítica , Fermentação , Cinética , Modelos Estatísticos , Fosfatos/química , Xilose/química , Leveduras/metabolismo
17.
Sci China C Life Sci ; 52(12): 1131-9, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20016970

RESUMO

To express human insulin-like growth factor-I (hIGF-I) in transformed Bombyx mori cultured cells and silk glands, the transgenic vector pigA3GFP-hIGF-ie-neo was constructed with a neomycin resistance gene driven by the baculovirus ie-1 promoter, and with the hIGF-I gene under the control of the silkworm sericin promoter Ser-1. The stably transformed BmN cells expressing hIGF-I were selected by using the antibiotic G418 at a final concentration of 700-800 microg/mL after the BmN cells were transfected with the piggyBac vector and the helper plasmid. The specific band of hIGF-I was detected in the transformed cells by Western blot. The expression level of hIGF-I, determined by ELISA, was about 7800 pg in 5x10(5) cells. Analysis of the chromosomal insertion sites by inverse PCR showed that exogenous DNA could be inserted into the cell genome randomly or at TTAA target sequence specifically for piggyBac element transposition. The transgenic vector pigA3GFP-hIGF-ie-neo was transferred into the eggs using sperm-mediated gene transfer. Finally, two transgenic silkworms were obtained after screening for the neo and gfp genes and verified by PCR and dot hybridization. The expression level of hIGF-I determined by ELISA was about 2440 pg/g of silk gland of the transgenic silkworms of the G1 generation.


Assuntos
Bombyx/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Seda/metabolismo , Animais , Animais Geneticamente Modificados , Bombyx/citologia , Bombyx/genética , Linhagem Celular , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Glândulas Exócrinas/metabolismo , Feminino , Expressão Gênica , Vetores Genéticos/genética , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Fator de Crescimento Insulin-Like I/genética , Masculino , Proteínas Recombinantes de Fusão/genética , Transfecção
18.
Yi Chuan ; 31(12): 1248-58, 2009 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-20042393

RESUMO

For further research on number, type, composition and origin of Bombyx mori aminoacyl-tRNA synthetase (BmaaRS) genes, in silico cloning was performed with Bombyx mori genomic and EST databases. There might be two different sets of aaRS nuclear gene in Bombxy nori genome, which encode mitochondrial BmaaRS and cytoplasmic BmaaRS, respectively. Among BmaaRS genes, there were 2 genes encoding mitochondrial BmSerRS, but no genes encoding cytoplasmic BmHisRS and mitochondrial BmGlnRS, BmLysRS, BmGlyRS, and BmThrRS. The functions of these absent genes could be directly replaced by other proteins with similar functions, or might undergo their distinct BmaaRS functions based on the alternative splice of one certain BmaaRS mRNA. Evidence of EST indicated that BmaaRS performed different alternative splicing patterns. The homology comparison and advanced structural analysis of BmaaRS demonstrated the existence of extended domains of BmaaRS. This is because some different BmaaRSs contained similar domain. Moreover, BmaaRSs with similar functions possessed the similar tertiary structure. Phylogenetic analysis revealed that BmaaRS encoded by two various sources of BmaaRS genes. Mitochondrial and cytoplasmic BmaaRS had different origin.


Assuntos
Aminoacil-tRNA Sintetases/genética , Bombyx/enzimologia , Proteínas de Insetos/genética , Aminoacil-tRNA Sintetases/química , Aminoacil-tRNA Sintetases/metabolismo , Animais , Bombyx/química , Bombyx/classificação , Bombyx/genética , Citoplasma/química , Citoplasma/enzimologia , Citoplasma/genética , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Mitocôndrias/química , Mitocôndrias/enzimologia , Mitocôndrias/genética , Conformação Molecular , Dados de Sequência Molecular , Família Multigênica , Filogenia
19.
Bioresour Technol ; 100(3): 1501-4, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18930393

RESUMO

The effect of different gases, CO(2) concentration, and separation of CO(2) from reaction system on photo-fermentation H(2) production was investigated by batch culture in this study. Experimental results showed that different gases (Ar,N(2),CO(2), and air) as gas phase have obviously affected on photo-H(2) production and a high concentration of CO(2) can inhibit the growth and H(2) evolution of Rhodopseudomonas faecalis RLD-53. When CO(2) concentration at 5%, cell increased most rapidly the specific growth rate of 0.489 g/l/h and the specific growth rate fell to be 0.265 g/l/h when CO(2) concentration at 40%. However, the growth of RLD-53 at CO(2) concentration of 60-100% was almost completely inhibited. At CO(2) concentrations of 5% and 10%, the maximum H(2) yield was 2.54 and 2.59 mol-H(2)/mol acetate, respectively, and it was similar with the control (2.61 mol-H(2)/mol acetate). H(2) not produced when CO(2) concentration at 60-100%. In conclusion, separation of CO(2) from reaction system can stimulate H(2) production in the entire photo-H(2) production process and H(2) yield increased about 12.8-18.85% than the control.


Assuntos
Dióxido de Carbono/isolamento & purificação , Dióxido de Carbono/metabolismo , Hidrogênio/metabolismo , Rodopseudomonas/fisiologia , Rodopseudomonas/efeitos da radiação , Luz , Fotobiologia/métodos
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