To isolate the bioflocculant-producing bacteria from activated sludge and investigate the flocculating characteristics of the newly isolated bioflocculant. Methods Bacteria were screened from activated sludge samples ...To isolate the bioflocculant-producing bacteria from activated sludge and investigate the flocculating characteristics of the newly isolated bioflocculant. Methods Bacteria were screened from activated sludge samples to isolate bioflocculant-producing bacteria. Flocculating activity was used as a measure of the flocculating capability of the bioflocculant. Results A novel bioflocculant-producing bacterium was isolated, which was identified to belong to genus Aeromonas and named as Aeromonas sp. Nil. Flocculating activity increased in the presence of K, Na^＋, or Ca^2＋. The highest flocculating activities for kaolin suspension were obtained in acidic pH ranges, and optimum pHs for it were 3.0, 4.0, and 5.0 with 1 mmol/L K^＋, Ca^＋, and Na^＋ present, respectively. The highest flocculating activities for soil suspension were observed at pH 8.0. The bioflocculant had a good flocculating activity and could achieve a flocculating activity of 92.4% for kaolin suspension at a dosage of only 1 mg.L-1, and its activity in kaolin suspension was decreased by only 9.2% after heating at 100℃ for 60 min. Conclusion The bioflocculant produced by Aeromonas sp. Nil has strong flocculating activity and high stability, which affords high possibility of its practical use.展开更多
Host associated probiotics(HAPs)provide health benefits to the host when administered as dietary supplement.However,a short-term probiotics application strategy has yet to be optimized.A 90-days study was conducted to...Host associated probiotics(HAPs)provide health benefits to the host when administered as dietary supplement.However,a short-term probiotics application strategy has yet to be optimized.A 90-days study was conducted to evaluate the response of Malaysian mahseer,Tor tambroides post larvae fed with basal diet enriched HAPs for 30-days,and its response following another 60-days feeding with only basal diet.Three experimental diets(Enterococcus faecalis strain 2674(T1),Aeromonas sp.strain A8-29(T2)and E.faecalis strain FC11682(T3))were prepared by spray-coating each HAPs on a basal diet at 1×108 CFU/g feed.Differences in growth performances,whole-body proximate and fatty acid composition,muscle morphometry,and gut morphology were evaluated.Results showed that after 30 days,T3 fish produced highest growth.All HAP treatment groups showed better muscle distribution profile,improved fatty acid composition,and higher villus length,width and area,than control group.After 90 days,the growth of T3 fish was still the highest.Muscle distribution profile and villus growth were higher in HAP treatments,although only total n-6 PUFA,total MUFA,linoleic acids,and linolenic acids in HAP treated fish remained high after probiotics withdrawal.No difference in whole-body proximate composition was observed in both 30 and 90 days.Collective findings demonstrated that short-term application of HAPs at an early stage could be used to boost T.tambroides growth,with E.faecalis strain FC11682 showing the best efficacy.展开更多
文摘To isolate the bioflocculant-producing bacteria from activated sludge and investigate the flocculating characteristics of the newly isolated bioflocculant. Methods Bacteria were screened from activated sludge samples to isolate bioflocculant-producing bacteria. Flocculating activity was used as a measure of the flocculating capability of the bioflocculant. Results A novel bioflocculant-producing bacterium was isolated, which was identified to belong to genus Aeromonas and named as Aeromonas sp. Nil. Flocculating activity increased in the presence of K, Na^＋, or Ca^2＋. The highest flocculating activities for kaolin suspension were obtained in acidic pH ranges, and optimum pHs for it were 3.0, 4.0, and 5.0 with 1 mmol/L K^＋, Ca^＋, and Na^＋ present, respectively. The highest flocculating activities for soil suspension were observed at pH 8.0. The bioflocculant had a good flocculating activity and could achieve a flocculating activity of 92.4% for kaolin suspension at a dosage of only 1 mg.L-1, and its activity in kaolin suspension was decreased by only 9.2% after heating at 100℃ for 60 min. Conclusion The bioflocculant produced by Aeromonas sp. Nil has strong flocculating activity and high stability, which affords high possibility of its practical use.
基金funded by Universiti Malaysia Terengganu under the Research Intensified Grant Scheme (RIGS VOT NO 55192/5).
文摘Host associated probiotics(HAPs)provide health benefits to the host when administered as dietary supplement.However,a short-term probiotics application strategy has yet to be optimized.A 90-days study was conducted to evaluate the response of Malaysian mahseer,Tor tambroides post larvae fed with basal diet enriched HAPs for 30-days,and its response following another 60-days feeding with only basal diet.Three experimental diets(Enterococcus faecalis strain 2674(T1),Aeromonas sp.strain A8-29(T2)and E.faecalis strain FC11682(T3))were prepared by spray-coating each HAPs on a basal diet at 1×108 CFU/g feed.Differences in growth performances,whole-body proximate and fatty acid composition,muscle morphometry,and gut morphology were evaluated.Results showed that after 30 days,T3 fish produced highest growth.All HAP treatment groups showed better muscle distribution profile,improved fatty acid composition,and higher villus length,width and area,than control group.After 90 days,the growth of T3 fish was still the highest.Muscle distribution profile and villus growth were higher in HAP treatments,although only total n-6 PUFA,total MUFA,linoleic acids,and linolenic acids in HAP treated fish remained high after probiotics withdrawal.No difference in whole-body proximate composition was observed in both 30 and 90 days.Collective findings demonstrated that short-term application of HAPs at an early stage could be used to boost T.tambroides growth,with E.faecalis strain FC11682 showing the best efficacy.
