Strain HIT-3,which has good performances in cellulose degradation,was isolated from the campus soil. Based on the identification of conservative sequences 16S rDNA and the analysis of physiological-biochemical charact...Strain HIT-3,which has good performances in cellulose degradation,was isolated from the campus soil. Based on the identification of conservative sequences 16S rDNA and the analysis of physiological-biochemical characteristics,HIT-3 was identified as Achromobacter xylosoxidans. Denitrificans. A two-step fermentation process was conducted by adopting compound-bioflocculant-producing flora constructed by cellulose-degrading bacterium HIT-3 and flocculating bacterium F2. The cellulose degradation metabolites of HIT-3 was taken as substrates by flocculating bacterium F2,by which excellent compound bio-flocculant was obtained. In addition,the enzymology characteristics of HIT-3 were investigated when cultured in cellulose media,which utilized CMC-Na as its sole carbon. The results show that HIT-3 achieves a climax of 67.6 U/mL of enzyme production after incubation for 6 d,and the organic carbons produced are sufficient as the substrates required by the fermentation of flocculating bacterium F2(flocculating efficiency of 85.6%),which makes it feasible to reuse bioenergy.展开更多
This study evaluates the influence of growth parameters such as pH, temperature, Carboxy Methyl Cellulose (CMC) concentration and agitation on cellulase production from three bacterial strains, viz., Achromobacter xyl...This study evaluates the influence of growth parameters such as pH, temperature, Carboxy Methyl Cellulose (CMC) concentration and agitation on cellulase production from three bacterial strains, viz., Achromobacter xylosoxidans BSS4, Bacillus sp. BSS3 and Pseudomonas sp. BSS2 isolated from the wood-yards on Kallai river bank in Kerala. Production of cellulase by these isolates was detected using basal salt medium (BSM) with 0.5% CMC as supplement, and CMCase activity was confirmed by iodine test. Dinitrosalicylic acid method was employed for assaying the cellulase production by measuring the amount of glucose liberated in μmol/mL/min. Maximum enzyme production from Pseudomonas sp. BSS2 was at pH 8, 37℃ with 1% CMC and 150 rpm, and cellulase production increased from initial 49.84 U/mL to 91.28 U/mL after optimization. The highest enzyme activity from Bacillus sp. BSS3 was at pH 9, 37℃ with 1% CMC, 150 rpm, and cellulase production increased from initial 26.05 U/mL to 104.68 U/mL after optimization. The maximum enzyme production from A. xylosoxidans BSS4 was at pH 7, 40℃ with 0.5% CMC and 150 rpm, and cellulase production increased from initial 55.28 U/mL to 68.37 U/mL after optimization. Thus among the three isolates, Bacillus sp. BSS3 showed maximum enzyme yield which can be explored for further scale up studies with an industrial perspective.展开更多
基金Sponsored by the National Basic Research Program of China (Grant No. 2004CB418505)
文摘Strain HIT-3,which has good performances in cellulose degradation,was isolated from the campus soil. Based on the identification of conservative sequences 16S rDNA and the analysis of physiological-biochemical characteristics,HIT-3 was identified as Achromobacter xylosoxidans. Denitrificans. A two-step fermentation process was conducted by adopting compound-bioflocculant-producing flora constructed by cellulose-degrading bacterium HIT-3 and flocculating bacterium F2. The cellulose degradation metabolites of HIT-3 was taken as substrates by flocculating bacterium F2,by which excellent compound bio-flocculant was obtained. In addition,the enzymology characteristics of HIT-3 were investigated when cultured in cellulose media,which utilized CMC-Na as its sole carbon. The results show that HIT-3 achieves a climax of 67.6 U/mL of enzyme production after incubation for 6 d,and the organic carbons produced are sufficient as the substrates required by the fermentation of flocculating bacterium F2(flocculating efficiency of 85.6%),which makes it feasible to reuse bioenergy.
文摘This study evaluates the influence of growth parameters such as pH, temperature, Carboxy Methyl Cellulose (CMC) concentration and agitation on cellulase production from three bacterial strains, viz., Achromobacter xylosoxidans BSS4, Bacillus sp. BSS3 and Pseudomonas sp. BSS2 isolated from the wood-yards on Kallai river bank in Kerala. Production of cellulase by these isolates was detected using basal salt medium (BSM) with 0.5% CMC as supplement, and CMCase activity was confirmed by iodine test. Dinitrosalicylic acid method was employed for assaying the cellulase production by measuring the amount of glucose liberated in μmol/mL/min. Maximum enzyme production from Pseudomonas sp. BSS2 was at pH 8, 37℃ with 1% CMC and 150 rpm, and cellulase production increased from initial 49.84 U/mL to 91.28 U/mL after optimization. The highest enzyme activity from Bacillus sp. BSS3 was at pH 9, 37℃ with 1% CMC, 150 rpm, and cellulase production increased from initial 26.05 U/mL to 104.68 U/mL after optimization. The maximum enzyme production from A. xylosoxidans BSS4 was at pH 7, 40℃ with 0.5% CMC and 150 rpm, and cellulase production increased from initial 55.28 U/mL to 68.37 U/mL after optimization. Thus among the three isolates, Bacillus sp. BSS3 showed maximum enzyme yield which can be explored for further scale up studies with an industrial perspective.
文摘从食草动物的粪便中经筛选分离到1株能降解纤维素的放线菌,经初步鉴定为Streptomycesspp.。对其在以秸秆为惟一碳源的培养基上的产酶条件进行研究,结果表明,最适摇瓶发酵产酶条件为以硫酸铵为氮源,采用种龄72 h的菌液接种,在接种量10%、培养基装量1/10、培养温度30℃时,发酵60 h CMCase活力可达4.5 u/mL。
