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Effect of leachate recycle and inoculation on microbial characteristics of municipal refuse in landfill bioreactors

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Journal of Environmental Sciences 2001年第4期13卷 508-513页

作者： Shen, D.-s. He, R. Ren, G.-p. Traore, I. Feng, X.-s. Dept. of Environment and Resource Zhejiang University Hangzhou 310029 China

Population development of key groups of anaerobic and aerobic bacteria involved in municipal refuse decomposition under laboratory landfill bioreactors with and without leachate recycle and inoculation was measured since modeling municipal refuse was landfilled in bioreactors for about 210 days. Hydrolytic fermentative bacteria (HFB), hydrogen-producing acetogenic bacteria (HPAB), methane-producing bacteria (MPB), sulfate-reducing bacteria (SRB), anaerobic and aerobic cellulolytic bacteria and denitrabacteria were enumerated by the most probable number technique. The results showed that the dominant microorganism groups were the methanogenic bacteria including hydrolytic fermentative, hydrogen-producing acetogenic and methane-producing bacteria. They were present in fresh refuse but at low values and positively affected by leachate recycle and refuse inoculation. The amounts of HFB or HPAB in digesters D4 and D5 operated with inoculation and leachate recycle reached their maximum values of 1010 - 1012 cells/g dry refuse for HFB or 105 - 106 cells/g dry refuse for HPAB on day 60, in digester D3 operated with leachate recycle on day 120 for HFB (109 cells/g dry refuse) or on day 90 for HPAB (105 cells/g dry refuse), and in digesters D1 and D2 on day 210 for HFB (109 cells/g dry refuse) or on day 90 for HPAB (104 - 106 cells/g dry refuse). The population of methane-producing bacteria in digesters D4 and D5 sharply increased on days 60 and 90 respectively, however in digesters D1, D2 and D3 on day 120. Leachate recycle and inoculation changed the cellulolytic microorganisms composition of refuse ecosystem, the higher amounts of anaerobic cellulolytic bacteria were measured in digesters D4 and D5 (107 cells/g dry refuse), followed by digesters D3 (106 cells/g dry refuse), D2 or D1 (104 cells/g dry refuse). However, the amounts of aerobic cellulolytic bacteria were much lower than that of anaerobic cellulolytic bacteria. And it was higher in digesters D3 than those in digesters D1, D2, D4 and D5. The amounts of SRB and

关键词： Bacteria Bioreactors fermentation Hydrolysis Land fill Microorganisms

ETHANOL fermentation OF MIXED GLUCOSE AND XYLOSE BY PICHIA STIPITIS

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Chinese Journal of Chemical Engineering 1994年第4期2卷 36-43页

作者：郑重鸣丁新华林建平张定丰岑沛霖

Pichia stipitis CBS 5773 yeast cells were used to ferment the mixed substrates consisted of glucose andxylose to produce ethanol.The effects of aeration rate,initial substrate concentration and pH on substrateutilization and ethanol yield were evaluated.During batch fermentation,the oscillation phenomena in cell growthwere observed at low aeration rate,whereas the diauxic growth at high aeration rate.The substrate utilizationratio and ethanol yield reached 95％ and 0.46g/g respectively under appropriate operation conditions.Amodified unstructural model was proposed to simulate the diauxic cell growth,substrate consumption andproduct formation.

关键词： ethanol fermentation mixed glucose and xylose Pichia stipitis

Metabolic flux analysis on arachidonic acid fermentation

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Frontiers of Chemical Science and Engineering 2007年第4期1卷 421-426页

作者： JIN Mingjie HUANG He ZHANG Kun YAN Jie GAO Zhen College of Life Science and Pharmaceutical Engineering Nanjing University of TechnologyNanjing 210009China

The analysis of flux distributions in metabolic networks has become an important approach for understand-ing the fermentation characteristics of the process.A model of metabolic flux analysis of arachidonic acid(AA)synthesis in Mortierella alpina ME-1 was established and carbon flux distributions were estimated in different fermentation phases with different concentrations of N-source.During the expo-nential,decelerating and stationary phase,carbon fluxes to AA were 3.28%,8.80%and 6.97%,respectively,with sufficient N-source broth based on the flux of glucose uptake,and those were increased to 3.95%,19.21%and 39.29%,respectively,by regulating the shifts of carbon fluxes via fermentation with limited N-source broth and adding 0.05% NaNO_(3) at 96 h.Eventually AA yield was increased from 1.3 to 3.5 g·L^(−1).These results suggest a way to improve AA fermentation,that is,fermentation with limited N-source broth and adding low concentration N-source during the stationary phase.

关键词： metabolic flux analysis arachidonic acid Mortierella alpina fermentation synthesis

Influence of furfural concentration on growth and ethanol yield of Saccharomyces kluyveri

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Journal of Environmental Sciences 2007年第12期19卷 1528-1532页

作者： LU Peng CHEN Li-jun Li Guo-xue SHEN Shi-hua WANG Li-li JIANG Qi-yang ZHANG Jin-feng College of Resources and Environment China Agricultural University Beijing 100094 China Institute of Botany Chinese Academy of Sciences Beijing 100093 China

Furfural is an important inhibitor in ethanol fermentation process using lignocellulosic hydrolysates as raw materials. In order to find out the furfural concentration range in which furfural inhibits the fermentation process, we used one strain Saccharomyces kluyveri selected from soil and cultured in several different furfural content media under low glucose concentration condition. Experiment results showed that microorganism growth was stimulated and dry cell weight decreased when furfural concentration in the medium was 0.25 mg/ml. Furfural had negative effect on cell growth when its concentration was above 1.00 mg/ml. At the same time, the strain growed better and had a higher glucose consumption rate in 5% original glucose concentration condition than in 3% original glucose concentration condition. The results showed that appropriate exaltation of original glucose concentration in stalk hydrolysates will increase the strain resistance to furfural.

关键词： furfural concentration Saccharomyces kluyveri fermentation growth ethanol yield

Activated sludge-mediated biodegradation of dimethyl phthalate under fermentative conditions

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Journal of Environmental Sciences 2008年第8期20卷 922-926页

作者： MAHMOOD Qaisar Department of Botany Federal Government Post Graduate College Sector H-8 IslamabadPakistan

The biodegradation of dimethyl phthalate(DMP)was investigated under fermentative conditions in this study.The nature of the intermediate compounds and the extent of mineralization were probed using high-pressure liquid chromatography(HPLC)and liquid chromatography-mass spectrometry(LC-MS)methods.The fermentative bacteria were able to biodegrade the DMP under anaerobic conditions,with the biodegradation rate of 0.36 mg DMP/(L·h).The results demonstrated that the DMP degradation under fermentative conditions ...

关键词： activated sludge biodegradation dimethyl phthalate fermentation phthalic acid mineralization

fermentation Effect on the Nutrient and Antinutrient Composition of Senegalia macrostachyaand Parkia biglobosaSeeds: A Comparative Study

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Food and Nutrition Sciences 2020年第7期11卷 726-740页

作者： Aimée W. D. B. Guissou Charles Parkouda Coulibaly K. Anaïs Traoré Korotimi Edwige Bahanla Oboulbiga Aly Savadogo Département Technologie Alimentaire (DTA) Institut de Recherche en Sciences Appliquées et Technologies (IRSAT) Centre National de la Recherche Scientifique et Technologique (CNRST) Ouagadougou Burkina Faso Laboratoire de Biochimie et d’Immunologie Appliquée Département de Biochimie-Microbiologie Université Joseph Ki-Zerbo Ouagadougou Burkina Faso

This study aimed to evaluate the effect of the fermentation on the nutrient and antinutrient composition of Senegalia macrostachya and Parkia biglobosa seeds. For condiments production, the raw seeds were cleaned, cooked, drained, washed, cooked, drained and fermented. Results show that the pH increased (from 6.09 to 7.76 and from 6.99 to 7.92) from the onset of the fermentation till 48 h during fermentation of

关键词： Senegalia macrostachya Parkia biglobosa fermentation Nutrients Phytates

Dynamics of methanogenesis,ruminal fermentation and fiber digestibility in ruminants following elimination of protozoa: a meta-analysis

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Journal of Animal Science and Biotechnology 2019年第1期10卷 150-158页

作者： Zongjun Li Qi Deng Yangfan Liu Tao Yan Fei Li Yangchun Cao Junhu Yao College of Animal Science and Technology Northwest A&F University State Key Laboratory of Genetic Resources and Evolution Kunming Institute of ZoologyChinese Academy of Sciences College of Pastoral Agricultural Science and Technology Lanzhou University

Background: Ruminal microbes are vital to the conversion of lignocellulose-rich plant materials into nutrients for ruminants.Although protozoa play a key role in linking ruminal microbial networks,the contribution of protozoa to rumen fermentation remains controversial; therefore,this meta-analysis was conducted to quantitatively summarize the temporal dynamics of methanogenesis,ruminal volatile fatty acid(VFA) profiles and dietary fiber digestibility in ruminants following the elimination of protozoa(also termed defaunation).A total of 49 studies from 22 publications were evaluated.Results: The results revealed that defaunation reduced methane production and shifted ruminal VFA profiles to consist of more propionate and less acetate and butyrate,but with a reduced total VFA concentration and decreased dietary fiber digestibility.However,these effects were diminished linearly,at different rates,with time during the first few weeks after defaunation,and eventually reached relative stability.The acetate to propionate ratio and methane production were increased at 7 and 11 wk after defaunation,respectively.Conclusions: Elimination of protozoa initially shifted the rumen fermentation toward the production of more propionate and less methane,but eventually toward the production of less propionate and more methane over time.

关键词： Defaunation Fiber digestibility Meta-analysis Methane production Rumen fermentation

fermentation of the Straw Material Paja Brava by the Yeast Pichia stipitisin a Simultaneous Saccharification and fermentation Process

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Journal of Sustainable Bioenergy Systems 2013年第2期3卷 99-106页

作者： Cristhian Carrasco Henrique Baudel Christian Roslander Mats Galbe Gunnar Lidén Department of Chemical Engineering Federal University of Pernambuco Recife Brazil Department of Chemical Engineering Lund University Lund Sweden

Paja Brava is a native South American grass with a high carbohydrate content. In the current work, the potential of using this feedstock for ethanol production using a simultaneous saccharification and fermentation (SSF) process with the xylose-fermenting yeast Pichia stipitis (Scheffersomyces stipitis) CBS6054 was investigated. The straw material was subjected to SO2 catalyzed steam pretreatment at 200°C and 5 min residence time, which resulted in a solubilization of pentose sugars (mainly xylose) of 64% with only minor amounts of degradation products. The obtained material, including the pretreatment liquid, was subsequently hydrolyzed and fermented in an SSF process at microaerobic conditions using either a batch or a fed-batch process at a total water-insoluble solids loading of 10%. Overall yields of ethanol based on all available sugars of 0.24 g/g and 0.27 g/g were obtained for batch and fed-batch mode of operation, respectively. The higher yield in the fed-batch process coincided with a higher degree of conversion of the sugars in the liquid medium, in particular of arabinose, for which the conversion was doubled (from 48% to 97%).

关键词： Ethanol Lignocellulose fermentation Xylose

Feed nutritional value of brewers’ spent grain residue resulting from protease aided protein removal

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Journal of Animal Science and Biotechnology 2020年第1期11卷 147-156页

作者： Yizhao Shen Ranithri Abeynayake Xin Sun Tao Ran Jianguo Li Lingyun Chen Wenzhu Yang College of Animal Science and Technology Hebei Agricultural UniversityBaoding 071029HebeiRepublic of China Agriculture and Agri-Food of Canada Lethbridge Research and Development CentreLethbridgeAB AB T1J4B1Canada Department of Agricultural Food&Nutritional Science University of AlbertaEdmontonAB T6G 2P5Canada College of Food Science and Engineering Shandong Agricultural UniversityTaian 271000ShandongRepublic of China.

Background:This study was conducted to evaluate the feed nutritional value of brewers’spent grain(BSG)residue resulting from protease aided protein removal.The nutritional value was measured as nutrient content,gas production,nutrient digestibility and fermentation characteristics in batch culture.Results:Protein extraction process decreased content of crude protein but concentrated the neutral detergent fibre(NDF)and ferulic acid in BSG residue.The changes in the chemical composition of BSG residue varied with enzyme and enzyme dosage.Digestibility of dry matter(DMD)and NDF of residue differed among proteases.Increasing alcalase dosage linearly decreased DMD,whereas,the DMD linearly increased as everlase or flavourzyme dosage increased.Compared with BSG,the DMD,gas production and fermentation acid concentration of BSG residues were lower,whereas NDF digestibility was higher.Conclusions:The substantially increased NDF content and improved in vitro NDF digestibility due to protease hydrolysis suggest that BSG residue can be potentially exploited as a viable fibre source for ruminant feeding.

关键词： Batch culture Brewers’spent grain Chemical composition fermentation Protease hydrolysis