The effects of initial substrate (5-60 g /L) and biomass concentration (0.5-3 g /L) on fermentative hydrogen production by mixed cultures were investigated in batch tests using glucose as substrate.The experimental re...The effects of initial substrate (5-60 g /L) and biomass concentration (0.5-3 g /L) on fermentative hydrogen production by mixed cultures were investigated in batch tests using glucose as substrate.The experimental results showed that the hydrogen production increases as the initial substrate concentration increases from 0 to 25 g /L.It indicated that the shift in the metabolic pathway or in the composition of the bacterial flora occurs.The maximum hydrogen yield of 1.78 mol /mol-glucose is obtained at the substrate concentration of 15 g /L.This study also shows that initial biomass concentration affects the hydrogen yield as the cumulative hydrogen production has been increased with the increase of initial cell concentration up to 1.5 g /L and reached the highest level.The maximum hydrogen yield is obtained at the cell concentration of 1.5 g /L.It indicated that the optimum biomass /substrate ratio,maximizing the hydrogen yield and the hydrogen production rate,is determined to be 0.1 g biomass /g glucose.展开更多
Tea polyphenols(TP),a natural ingredient recognized for their potent antioxidant and antimicrobial properties,are the focus for extending the freshness and shelf life of apple juices in preservation.This study evaluat...Tea polyphenols(TP),a natural ingredient recognized for their potent antioxidant and antimicrobial properties,are the focus for extending the freshness and shelf life of apple juices in preservation.This study evaluated the nutritional quality,microbial growth,and sensory changes in apple juice during storage,examining the impact of TP addition on both freshly pressed and retail high-pressure processing(HPP)apple juice.For fresh apple juice,the growth of total colonies was predicted using a Modified Gompertz model.The results showed that the addition of 0.6 g/kg TP to fresh apple juice reduced the total number of colonies by 1.54 times after 11 days of storage,while the addition of 0.6 g/kg TP to retail HPP apple juice reduced the total number of colonies by 2.15 times after 20 days.In addition,apple juice treated with 0.6 g/kg of TP had good antioxidant and sensory properties compared to the control.These results indicated that the application of TP could increase the antioxidant capacity of apple juice,enhance their taste and prolong their shelf life.展开更多
基金Sponsored by the State Key Laboratory of Urban Water Resource and Environment of Harbin Institute of Technology(Grant No.2010DX06)the National High Technology Research and Development Program of China(Grant No.2006AA05Z109)the Harbin Science and Technology Bureau(Grant No.2009RFXXS004)
文摘The effects of initial substrate (5-60 g /L) and biomass concentration (0.5-3 g /L) on fermentative hydrogen production by mixed cultures were investigated in batch tests using glucose as substrate.The experimental results showed that the hydrogen production increases as the initial substrate concentration increases from 0 to 25 g /L.It indicated that the shift in the metabolic pathway or in the composition of the bacterial flora occurs.The maximum hydrogen yield of 1.78 mol /mol-glucose is obtained at the substrate concentration of 15 g /L.This study also shows that initial biomass concentration affects the hydrogen yield as the cumulative hydrogen production has been increased with the increase of initial cell concentration up to 1.5 g /L and reached the highest level.The maximum hydrogen yield is obtained at the cell concentration of 1.5 g /L.It indicated that the optimum biomass /substrate ratio,maximizing the hydrogen yield and the hydrogen production rate,is determined to be 0.1 g biomass /g glucose.
基金supported by the National Natural Science Foundation of China(grant numbers 32101907,32202003)Shanghai Jiao Tong University State Key Laboratory of Microbial Metabolism(grant number MMLKF22-09).
文摘Tea polyphenols(TP),a natural ingredient recognized for their potent antioxidant and antimicrobial properties,are the focus for extending the freshness and shelf life of apple juices in preservation.This study evaluated the nutritional quality,microbial growth,and sensory changes in apple juice during storage,examining the impact of TP addition on both freshly pressed and retail high-pressure processing(HPP)apple juice.For fresh apple juice,the growth of total colonies was predicted using a Modified Gompertz model.The results showed that the addition of 0.6 g/kg TP to fresh apple juice reduced the total number of colonies by 1.54 times after 11 days of storage,while the addition of 0.6 g/kg TP to retail HPP apple juice reduced the total number of colonies by 2.15 times after 20 days.In addition,apple juice treated with 0.6 g/kg of TP had good antioxidant and sensory properties compared to the control.These results indicated that the application of TP could increase the antioxidant capacity of apple juice,enhance their taste and prolong their shelf life.
