高酵母接种量的抑菌特性及其在蔗汁生产乙醇中的应用

研究了高酵母菌接种量的抑菌特性及对蔗汁乙醇发酵过程的影响。混合杂菌与酵母以不同浓度配比接入蔗汁发酵培养基中发酵,当增加酵母接种量达到5×10~7个/mL时,醪液中乙醇浓度没有明显降低。利用鲜甘蔗汁直接发酵时,接种量为5×10~7个/mL,乙醇产量达10.54%(20℃,v/v),与使用经高温灭菌的甘蔗汁作培养基,酵母接种量为2×10~7个/mL时相当,但发酵速度明显快于后者。其发酵上清液中未检出抑菌成分,说明提高酵母的接种量可以有效抑菌,其原因可能是酵母的生长处于竞争优势,抑制了杂菌的生长代谢。该研究为蔗汁发酵生产燃料乙醇,降低染菌风险提供了有效的尝试。

Study on the Bacteriostatic Action of High Yeast Inoculation and the Application in the Fermentation of Sugarcane Juice to Produce Ethanol

This paper mainly studied the bacteriostatic action of high yeast inoculation and the effects on the fermentation of sugarcane juice to produce ethanol.Experiments were conducted using varies concentra- tions of the bacteria together with Saccharomyces cerevisiae.It was interesting to observe that increase the yeast inoculation rates of 5×10~7 cells/mL made no differences(P>0.2)in the final ethanol at any contami- nation levels,even when the sugarcane juice was infected with 1×10~8 bacteria/mL.Compared with the fer- mentation of sterilized sugarcane juice at standard recommendation inoculation of 2×10~7 cells/mL,no reduc- tion was observed in the final ethanol concentration in the fermentation of fresh sugarcane juice(unsterilized) at the inoculation rate of 5×10~7 cells/mL,as the ethanol concentration was 10.54%(20℃,v/v).Also the fermentation rate was improved.However,the yeast supernatant was evaluated by liquid culture of Lactobacillus plantrum,there is no inhibitory effect was found on the bacterial growth.This results demon- strated that a high yeast inoculation at the start of the sugarcane juice fermentation allows the yeast outgrow the contaminant bacteria and inhibits its growth and metabolism.This study put forward a novel approach to minimize the effects caused by bacterial contamination during industrial production of ethanol from sugarcane juice.