The biodegradability of Aspergillus niger （A. niger）, Mucor （M-305） and Trichoderma（T-311） strains on regenerated cellulose films in media was investigated. The results showedthat T-311 strain isolated from soil...The biodegradability of Aspergillus niger （A. niger）, Mucor （M-305） and Trichoderma（T-311） strains on regenerated cellulose films in media was investigated. The results showedthat T-311 strain isolated from soil adhered on the cellulose film fragments has strongerdegradation effect on the cellulose film than A. niger strain. The weights, molecular weightsand tensile strengths of the cellulose films in both shake culture and solid media decreasedwith incubation time, accompanied by producing CO<sub>2</sub> and saccharides. HPLC, IR and re-leased CO<sub>2</sub> analysis indicated that the biodegradation products of the regenerated cellulosefilms mainly contain oligosaccharides, cellobiose, glucose, arabinose, erythrose, glycerose,glycerol, ethanal, formaldehyde and organic acid, the end products were CO<sub>2</sub> and water.After a month, the films were completely decomposed by fungi in the media at 30℃.展开更多
A fungus(WR-C1) decomposed cellulose was isolated from a hypothermal litter layer using Congo red medium as the preliminary screening culture medium and then using a filter as the secondary screening medium at low tem...A fungus(WR-C1) decomposed cellulose was isolated from a hypothermal litter layer using Congo red medium as the preliminary screening culture medium and then using a filter as the secondary screening medium at low temperature. The experiment showed that the weight loss rate of filter paper on the 15 th days could reach 30.69%. A morphologic and ITS gene sequence analysis suggested that CF-C1 was Cladosporium. We mainly studied the effects of culture time, inoculation amount, initial p H and different sources of carbon, nitrogen and inorganic salt on the cellulase production of strain WR-C1. Under optimum cultural condition, the highest value of WR-C1 enzyme production and filter paper enzyme were 3.27 U · m L^(-1) and 0.51 U · m L^(-1).展开更多
As the abundant biopolymer, cellulose can be used as a feedstock for chemicals and materials. Effective conversion of cellulose by simple processes is a key point. Degradation of cellulose in its homogeneous solution ...As the abundant biopolymer, cellulose can be used as a feedstock for chemicals and materials. Effective conversion of cellulose by simple processes is a key point. Degradation of cellulose in its homogeneous solution is attractive for the molecular chains are free and spread. Here,microcrystalline cellulose was first dissolved in aqueous solution of Na OH and urea, and then hydrothermal reaction was carried out at various temperature and time. Fluorescence carbon dots(CDs) were generated accompanied with six organic acids: oxalic acid, formic acid, malonic acid, lactic acid, acetic acid, and fumaric acid. The yields of all organic acids and CDs, and the fluorescence quantum yield(QY) of CDs were studied at different reaction conditions. It was found that the maximum yield of organic acids and CDs are 80.1% and 6.03%, respectively, and the highest QY of the CDs is 10.9%. Fluorescence studies reveal that the as-prepared CDs has efficient selectivity and sensitivity toward iron ions in acidic condition, indicating it is a potential fluorescent sensor to the detection of Fe3+. Importantly, it provides a panorama to summary the degradation routes of cellulose in its homogeneous aqueous solution with both organic molecules and CDs as products.展开更多
The effect of inoculation with arbuscular mycorrhizal(AM) fungi( Acaulospora lavis ) on the degradation of di(2 ethylhexyl) phthalate(DEHP) in soil was studies. Cowpea plants (Pigna sinensis) were used as host plants ...The effect of inoculation with arbuscular mycorrhizal(AM) fungi( Acaulospora lavis ) on the degradation of di(2 ethylhexyl) phthalate(DEHP) in soil was studies. Cowpea plants (Pigna sinensis) were used as host plants and grown in a specially designed rhizobox. The experimental results indicated that, both in sterile and non sterile soil, mycorrhizal colonization rates were much higher in the mycorrhizal plants than in the non mycorrhizal plants. Addition of 4 mg/kg DEHP slightly affected mycorrhizal colonization, but the addition of 100 mg/kg DEHP significantly decreased mycorrhizal colonization. DEHP degradation in the mycorrhizosphere(Ms) and hyphosphere(Hs), especially in the Hs, increased after inoculation with Acaulospora lavis . It is concluded that mycorrhizal hyphae play an important role in the plant uptake, degradation and translocation of DEHP. The mechanism might be attributed to increased numbers of bacteria and actinomycetes and activity of dehydrogenase, urease and acid phosphatase in the Ms and Hs by mycorrhizal fungi.展开更多
A composite microbial system, including a strain of Candida tropicalis(W3), a strain of Lactobacillus plantarm(WY3) and three strains of basidiomycete pL104, pL113 and C33, was chosen to degrade corn straw. The final ...A composite microbial system, including a strain of Candida tropicalis(W3), a strain of Lactobacillus plantarm(WY3) and three strains of basidiomycete pL104, pL113 and C33, was chosen to degrade corn straw. The final pH was acid owing to the inoculation of acidogenic bacteria, and under this condition the composite fungi system could produce complex enzyme to destroy the compact structure of corn straw. The experimental results showed that the biomass of composite fungi could reach up to maximum when the pH value was 4.5. Through the bio-degradation by combining acidogenic bacteria with the composite fungi system, the cellulose, hemi-cellulose and lignin degradation rates of corn straw powder were 26.36%, 43.30% and 26.96%, respectively. And the gross crude protein content increased 60.41%. This study provided the evidence for the feasibility of developing a composite microbial system with high capability of degrading straw lignocelluloses in order to make reasonable use of straw resource and protect rural eco-environment.展开更多
[Objectives]To isolate and identify characteristics of the cellulose-degrading bacteria.[Methods]In view of the poor effect of crop straw composting,the strains which can degrade cellulose were isolated and purified f...[Objectives]To isolate and identify characteristics of the cellulose-degrading bacteria.[Methods]In view of the poor effect of crop straw composting,the strains which can degrade cellulose were isolated and purified from the soil piled with rice straw,and the strains A2 and A5 with high efficiency of cellulose degradation were finally screened through the transparent circle,cellulase activity and filter paper disintegration experiments.[Results]It was confirmed that the strains A2 and A5 could degrade cellulose well.The results of 16s rDNA showed that A2 was Pseudoxanthomonas mexicana and A5 was Bacillus cibi.[Conclusions]The results of this study are expected to provide high-quality strain resources for the degradation of cellulose in straw,and have important application value for improving the efficiency of straw composting.展开更多
The process of the rice straw degradation in the fermentor with aeration at 290 ml/h was studied. The results of dissolved oxygen (DO) indicated that the optimum DO during cellulose degradation by microbial community ...The process of the rice straw degradation in the fermentor with aeration at 290 ml/h was studied. The results of dissolved oxygen (DO) indicated that the optimum DO during cellulose degradation by microbial community MC1 ranged from 0.01 to 0.12 mg/L. The change model of pH values was as follows: irrespective of the initial pH of the medium, pH values decreased rapidly to approximate 6.0 after being inoculated within 48 h when cellulose was strongly degraded, and then increased slowly to 8.0—9.0 until cellulose was degraded completely. During the degradation process, 15 kinds of organic compounds were checked out by GC-MS. Most of them were organic acids. Quantity analysis was carried out, and the maximum content compound was ethyl acetate which reached 13.56 g/L on the day 4. The cellulose degradation quantity and ratio analyses showed that less quantity (under batch fermentation conditions) and longer interval (under semi-fermentation conditions) of rice straw added to fermentation system were contributed to matching the change model of pH, and increasing the quantity and ratio of rice straw degradation during cellulose degrading process. The highest degradation ratio was observed under the condition of rice straw added one time every five days (under semi-fermentation conditions).展开更多
Paper and pulp mill is a source of major pollution generating industry leaving huge amount of intensely colored effluent to the receiving end. Rapid increase of population and the increased demand for industrial estab...Paper and pulp mill is a source of major pollution generating industry leaving huge amount of intensely colored effluent to the receiving end. Rapid increase of population and the increased demand for industrial establishments to meet human needs have created problems such as over exploitation of available resources, increased pollution taking place on land, air and water environment. The intention of this research paper is to identify predominant bacteria and fungi in paper and pulp mill effluent in addition to evaluate the degradation efficiency of individual isolates and combination of isolates. Treatment efficiency of individual isolates and combination of isolates are evaluated by shake flask method. Combination of Pseudomonas Alkaligenes, Bacillus subtilis along with Trichoderma reesei shows higher BOD, COD reduction of 99% and 85% respectively. As individual isolates Pseudomonas Alkaligenes show 92% BOD reduction and 77% COD reduction over other bacterial isolates and Trichoderma reesei removed 99% BOD and 80% COD respectively.展开更多
To accelerate the decomposition of wheat straw directly returned to soil, we constructed a microbial system (ADS-3) from agricultural soil containing rotting straw residues using a 40-wk limited cultivation. To assess...To accelerate the decomposition of wheat straw directly returned to soil, we constructed a microbial system (ADS-3) from agricultural soil containing rotting straw residues using a 40-wk limited cultivation. To assess its potential use for accelerating straw decomposing, the decomposing characteristics and the microbial composition of ADS-3 were analyzed. The results indicated that it could degrade wheat straw and filter paper by 63.8 and 80%, respectively, during 15 d of incubation. Straw hemicellulose degraded dramatically 51.2% during the first 3 d, decreasing up to 73.7% by the end of incubation. Cellulose showed sustained degradation reaching 53.3% in 15 d. Peak values of xylanase and cellulase activities appeared at 3 and 11 d, with 1.32 and 0.15 U mL-1, respectively. Estimated pH averaged 6.4-7.6 during the degradation process, which approximated acidity and alkalinity of normal soils. The microbial composition of ADS-3 was stable based on denaturing gradient gel electrophoresis (DGGE) analysis. By using bacterial 16S rRNA and fungal 26S rRNA gene clone library analysis, 20 bacterial clones and 7 fungal clones were detected. Closest identified relatives of bacteria represented by Bacillus fusiformis, Cytophaga sp., uncultured Clostridiales bacterium, Ruminobacillus xylanolyticum, Clostridium hydroxybenzoicum, and uncultured proteobacterium and the fungi were mainly identified as related to Pichia sp. and uncultured fungus.展开更多
Experimental results of an azo dye(reactive brilliant red X 3B, RBR X 3B) decolorization and degradation in a white rot fungal biofilm reactor were introduced and discussed. The fungal biofilm reactor is highly potent...Experimental results of an azo dye(reactive brilliant red X 3B, RBR X 3B) decolorization and degradation in a white rot fungal biofilm reactor were introduced and discussed. The fungal biofilm reactor is highly potential for dye decolorization and degradation with the highest decoloring rate of 95% within 96 hours reaction time at initial pH 4.5 under high nitrogen level (HN) (24 mmol/L ammonium tartrate) condition. Experimental conditions, such as nutrient nitrogen levels in reaction mixture and initial pH, significantly affected dye decolorization and degradation. Effluents from this biofilm reactor can be well treated to meet the discharging requirements by use of chemical flocculation.RBR X 3B was first absorbed onto fungal biomass and then degraded gradually. The SH 13 fungus monopolized the biofilm throughout the experiments, though the reactor was exposed to open air for 4 months.展开更多
This study is aimed at identifying and determining the percentage of occurrence frequency of cellulose decomposing soil fungi. The soil samples were inoculated into culture plates prepared in Sabouraud medium under st...This study is aimed at identifying and determining the percentage of occurrence frequency of cellulose decomposing soil fungi. The soil samples were inoculated into culture plates prepared in Sabouraud medium under sterilized conditions and incubated at 30 °C for 4 to 7 d. The identified fungal species were incubated in self-designed cellulose medium for testing their cellulolytic ability. Forty-two species, including 2 nova species, representing sixteen genera showed growth and sporulation in the cellulose medium. Most of the isolated species were from genus Aspergillus and Penicillium. Aspergillus niger and Mucor hie-malis showed highest occurrence frequency (45% and 36% respectively), as these species were collected from about 80% of soil samples. Being agar free and cheaper, the new fungal medium designed showed results equivalent to Sabouraud medium.展开更多
In this study,a cellulose-degrading bacterium was isolated from paddy soils in Chengdu City.After 2 d of culture,the average diameter of hydrolytic circles on CMC-Congo red medium was 26-30 mm.Single colonies on LB pl...In this study,a cellulose-degrading bacterium was isolated from paddy soils in Chengdu City.After 2 d of culture,the average diameter of hydrolytic circles on CMC-Congo red medium was 26-30 mm.Single colonies on LB plates were white and wrinkled.The isolated strain was identified as a Gram-negative bacterium by Gram staining,which could produce short rod-like spores.Colony PCR was performed using the bacterial 16S rDNA universal primers.A 1 429 kb DNA fragment was amplified.Based on sequence homology analysis and comprehensive analysis,the isolated strain was identified as Bacillus velezensis,which was named CDBV62 according to the origin.展开更多
基金The work ws supported by the State Economy and Trade Commission of China.
文摘The biodegradability of Aspergillus niger （A. niger）, Mucor （M-305） and Trichoderma（T-311） strains on regenerated cellulose films in media was investigated. The results showedthat T-311 strain isolated from soil adhered on the cellulose film fragments has strongerdegradation effect on the cellulose film than A. niger strain. The weights, molecular weightsand tensile strengths of the cellulose films in both shake culture and solid media decreasedwith incubation time, accompanied by producing CO<sub>2</sub> and saccharides. HPLC, IR and re-leased CO<sub>2</sub> analysis indicated that the biodegradation products of the regenerated cellulosefilms mainly contain oligosaccharides, cellobiose, glucose, arabinose, erythrose, glycerose,glycerol, ethanal, formaldehyde and organic acid, the end products were CO<sub>2</sub> and water.After a month, the films were completely decomposed by fungi in the media at 30℃.
基金Supported by the Post-doctoral Research Starting Fund of Heilongjiang Province(LBH-Q13020)
文摘A fungus(WR-C1) decomposed cellulose was isolated from a hypothermal litter layer using Congo red medium as the preliminary screening culture medium and then using a filter as the secondary screening medium at low temperature. The experiment showed that the weight loss rate of filter paper on the 15 th days could reach 30.69%. A morphologic and ITS gene sequence analysis suggested that CF-C1 was Cladosporium. We mainly studied the effects of culture time, inoculation amount, initial p H and different sources of carbon, nitrogen and inorganic salt on the cellulase production of strain WR-C1. Under optimum cultural condition, the highest value of WR-C1 enzyme production and filter paper enzyme were 3.27 U · m L^(-1) and 0.51 U · m L^(-1).
基金supported by the National Natural Science Foundation of China (No. 51373162 and 51673180)
文摘As the abundant biopolymer, cellulose can be used as a feedstock for chemicals and materials. Effective conversion of cellulose by simple processes is a key point. Degradation of cellulose in its homogeneous solution is attractive for the molecular chains are free and spread. Here,microcrystalline cellulose was first dissolved in aqueous solution of Na OH and urea, and then hydrothermal reaction was carried out at various temperature and time. Fluorescence carbon dots(CDs) were generated accompanied with six organic acids: oxalic acid, formic acid, malonic acid, lactic acid, acetic acid, and fumaric acid. The yields of all organic acids and CDs, and the fluorescence quantum yield(QY) of CDs were studied at different reaction conditions. It was found that the maximum yield of organic acids and CDs are 80.1% and 6.03%, respectively, and the highest QY of the CDs is 10.9%. Fluorescence studies reveal that the as-prepared CDs has efficient selectivity and sensitivity toward iron ions in acidic condition, indicating it is a potential fluorescent sensor to the detection of Fe3+. Importantly, it provides a panorama to summary the degradation routes of cellulose in its homogeneous aqueous solution with both organic molecules and CDs as products.
基金TheNationalKeyBasicScienceResearchProjectofChina (No .G1 9990 1 1 80 6)
文摘The effect of inoculation with arbuscular mycorrhizal(AM) fungi( Acaulospora lavis ) on the degradation of di(2 ethylhexyl) phthalate(DEHP) in soil was studies. Cowpea plants (Pigna sinensis) were used as host plants and grown in a specially designed rhizobox. The experimental results indicated that, both in sterile and non sterile soil, mycorrhizal colonization rates were much higher in the mycorrhizal plants than in the non mycorrhizal plants. Addition of 4 mg/kg DEHP slightly affected mycorrhizal colonization, but the addition of 100 mg/kg DEHP significantly decreased mycorrhizal colonization. DEHP degradation in the mycorrhizosphere(Ms) and hyphosphere(Hs), especially in the Hs, increased after inoculation with Acaulospora lavis . It is concluded that mycorrhizal hyphae play an important role in the plant uptake, degradation and translocation of DEHP. The mechanism might be attributed to increased numbers of bacteria and actinomycetes and activity of dehydrogenase, urease and acid phosphatase in the Ms and Hs by mycorrhizal fungi.
文摘A composite microbial system, including a strain of Candida tropicalis(W3), a strain of Lactobacillus plantarm(WY3) and three strains of basidiomycete pL104, pL113 and C33, was chosen to degrade corn straw. The final pH was acid owing to the inoculation of acidogenic bacteria, and under this condition the composite fungi system could produce complex enzyme to destroy the compact structure of corn straw. The experimental results showed that the biomass of composite fungi could reach up to maximum when the pH value was 4.5. Through the bio-degradation by combining acidogenic bacteria with the composite fungi system, the cellulose, hemi-cellulose and lignin degradation rates of corn straw powder were 26.36%, 43.30% and 26.96%, respectively. And the gross crude protein content increased 60.41%. This study provided the evidence for the feasibility of developing a composite microbial system with high capability of degrading straw lignocelluloses in order to make reasonable use of straw resource and protect rural eco-environment.
基金Supported by Innovation and Entrepreneurship Training Program for College Students (202310580018).
文摘[Objectives]To isolate and identify characteristics of the cellulose-degrading bacteria.[Methods]In view of the poor effect of crop straw composting,the strains which can degrade cellulose were isolated and purified from the soil piled with rice straw,and the strains A2 and A5 with high efficiency of cellulose degradation were finally screened through the transparent circle,cellulase activity and filter paper disintegration experiments.[Results]It was confirmed that the strains A2 and A5 could degrade cellulose well.The results of 16s rDNA showed that A2 was Pseudoxanthomonas mexicana and A5 was Bacillus cibi.[Conclusions]The results of this study are expected to provide high-quality strain resources for the degradation of cellulose in straw,and have important application value for improving the efficiency of straw composting.
基金This work was supported by the National Natural Science Foundation of China(No.30571088)the National Key Technology Research and Development Program of China during the 11th Five-Year Plan Period(No.2006BAD07A01,2006BAD25B04).
基金The Hi-Tech Research and Development Program (863) of China (No. 2002AA245031) the National Key Project of the"10thFive-Year"Program of China (No. 2002BA516A03)
文摘The process of the rice straw degradation in the fermentor with aeration at 290 ml/h was studied. The results of dissolved oxygen (DO) indicated that the optimum DO during cellulose degradation by microbial community MC1 ranged from 0.01 to 0.12 mg/L. The change model of pH values was as follows: irrespective of the initial pH of the medium, pH values decreased rapidly to approximate 6.0 after being inoculated within 48 h when cellulose was strongly degraded, and then increased slowly to 8.0—9.0 until cellulose was degraded completely. During the degradation process, 15 kinds of organic compounds were checked out by GC-MS. Most of them were organic acids. Quantity analysis was carried out, and the maximum content compound was ethyl acetate which reached 13.56 g/L on the day 4. The cellulose degradation quantity and ratio analyses showed that less quantity (under batch fermentation conditions) and longer interval (under semi-fermentation conditions) of rice straw added to fermentation system were contributed to matching the change model of pH, and increasing the quantity and ratio of rice straw degradation during cellulose degrading process. The highest degradation ratio was observed under the condition of rice straw added one time every five days (under semi-fermentation conditions).
文摘Paper and pulp mill is a source of major pollution generating industry leaving huge amount of intensely colored effluent to the receiving end. Rapid increase of population and the increased demand for industrial establishments to meet human needs have created problems such as over exploitation of available resources, increased pollution taking place on land, air and water environment. The intention of this research paper is to identify predominant bacteria and fungi in paper and pulp mill effluent in addition to evaluate the degradation efficiency of individual isolates and combination of isolates. Treatment efficiency of individual isolates and combination of isolates are evaluated by shake flask method. Combination of Pseudomonas Alkaligenes, Bacillus subtilis along with Trichoderma reesei shows higher BOD, COD reduction of 99% and 85% respectively. As individual isolates Pseudomonas Alkaligenes show 92% BOD reduction and 77% COD reduction over other bacterial isolates and Trichoderma reesei removed 99% BOD and 80% COD respectively.
基金supported by the National Key Technology R&D Program of China (2008BADC4B01 and 2008BADC4B17)the National Special Research Fund for Non-Profit Sector, China (200803033)
文摘To accelerate the decomposition of wheat straw directly returned to soil, we constructed a microbial system (ADS-3) from agricultural soil containing rotting straw residues using a 40-wk limited cultivation. To assess its potential use for accelerating straw decomposing, the decomposing characteristics and the microbial composition of ADS-3 were analyzed. The results indicated that it could degrade wheat straw and filter paper by 63.8 and 80%, respectively, during 15 d of incubation. Straw hemicellulose degraded dramatically 51.2% during the first 3 d, decreasing up to 73.7% by the end of incubation. Cellulose showed sustained degradation reaching 53.3% in 15 d. Peak values of xylanase and cellulase activities appeared at 3 and 11 d, with 1.32 and 0.15 U mL-1, respectively. Estimated pH averaged 6.4-7.6 during the degradation process, which approximated acidity and alkalinity of normal soils. The microbial composition of ADS-3 was stable based on denaturing gradient gel electrophoresis (DGGE) analysis. By using bacterial 16S rRNA and fungal 26S rRNA gene clone library analysis, 20 bacterial clones and 7 fungal clones were detected. Closest identified relatives of bacteria represented by Bacillus fusiformis, Cytophaga sp., uncultured Clostridiales bacterium, Ruminobacillus xylanolyticum, Clostridium hydroxybenzoicum, and uncultured proteobacterium and the fungi were mainly identified as related to Pichia sp. and uncultured fungus.
文摘Experimental results of an azo dye(reactive brilliant red X 3B, RBR X 3B) decolorization and degradation in a white rot fungal biofilm reactor were introduced and discussed. The fungal biofilm reactor is highly potential for dye decolorization and degradation with the highest decoloring rate of 95% within 96 hours reaction time at initial pH 4.5 under high nitrogen level (HN) (24 mmol/L ammonium tartrate) condition. Experimental conditions, such as nutrient nitrogen levels in reaction mixture and initial pH, significantly affected dye decolorization and degradation. Effluents from this biofilm reactor can be well treated to meet the discharging requirements by use of chemical flocculation.RBR X 3B was first absorbed onto fungal biomass and then degraded gradually. The SH 13 fungus monopolized the biofilm throughout the experiments, though the reactor was exposed to open air for 4 months.
文摘This study is aimed at identifying and determining the percentage of occurrence frequency of cellulose decomposing soil fungi. The soil samples were inoculated into culture plates prepared in Sabouraud medium under sterilized conditions and incubated at 30 °C for 4 to 7 d. The identified fungal species were incubated in self-designed cellulose medium for testing their cellulolytic ability. Forty-two species, including 2 nova species, representing sixteen genera showed growth and sporulation in the cellulose medium. Most of the isolated species were from genus Aspergillus and Penicillium. Aspergillus niger and Mucor hie-malis showed highest occurrence frequency (45% and 36% respectively), as these species were collected from about 80% of soil samples. Being agar free and cheaper, the new fungal medium designed showed results equivalent to Sabouraud medium.
文摘In this study,a cellulose-degrading bacterium was isolated from paddy soils in Chengdu City.After 2 d of culture,the average diameter of hydrolytic circles on CMC-Congo red medium was 26-30 mm.Single colonies on LB plates were white and wrinkled.The isolated strain was identified as a Gram-negative bacterium by Gram staining,which could produce short rod-like spores.Colony PCR was performed using the bacterial 16S rDNA universal primers.A 1 429 kb DNA fragment was amplified.Based on sequence homology analysis and comprehensive analysis,the isolated strain was identified as Bacillus velezensis,which was named CDBV62 according to the origin.
