title: [Impact of fermentation system initial status on oscillations in very high gravity ethanol continuous fermentation process and analysis of fermentation efficiency improvement].
abstract: Prior research reported the oscillatory behavior characterized by long period and high amplitude during high gravity continuous ethanol fermentations at the dilution rate of 0.027 h(-1). In this paper, high gravity continuous ethanol fermentations using Saccharomyces cerevisia at different dilution rates were carried out. Similar oscillations were observed when the dilution rate was switched to 0.04 h(-1). Both oscillatory and steady processes can be achieved at dilution rates of 0.027 or 0.04 h(-1), which depends on the initial status of the fermentation system. However, compared to steady process at the same dilution rate of 0.04 h(-1), the average residual sugar concentration was lowered by 14.8% for the oscillatory process, while the average ethanol concentration and productivity were increased by 12.6% and 12.3%, respectively. Further investigation revealed that besides the lag time, oscillatory processes were different from steady ones in kinetics because a higher specific growth rate can be achieved at the same residual sugar and ethanol concentrations (increased by 53.8% in average).
authors.affiliation: Engineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Technology and Business University, Chongqing 400067, China. 1981shenyu@sohu.com
authors.forename: Yu
authors.initials: Y
authors.lastname: Shen
authors.forename: Xumeng
authors.initials: X
authors.lastname: Ge
authors.forename: Fengwu
authors.initials: F
authors.lastname: Bai
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D002241:Carbohydrates; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D018471:Hypergravity; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D002241:Carbohydrates; D000431:Ethanol