对从谷氨酸连续等电结晶罐中分离得到的野生酵母菌株进行了初步的鉴定,并探寻了防治其污染的可能途径。结果表明,该酵母属于假丝酵母属,增殖过程中能够同化利用谷氨酸,是引起发酵液中谷氨酸含量下降的主要原因。通过对该野生酵母生长特性的分析可知,当温度高于50℃时其生长几乎停滞,pH在下降至等电点3.2时也能一定程度抑制其快速增殖。结合谷氨酸连续等电结晶过程特点,尝试缩短结晶停留时间来防治其污染,当停留时间低于9.12 h时,野生酵母被稀释洗脱,从而减少提取过程主产品谷氨酸的损失。

The wild yeast strain isolated from the continuous crystallization of L-glutamic acid production was preliminary identified and the possible approaches preventing its contamination were consequently investigated in this study.The results suggested that this wild yeast belongs to Candida and it could assimilate and utilize L-glutamic acid for its proliferation,causing the decrease of glutamic in the fermentation broth.Through analysis of the wild yeast's growth-characteristics,it could be concluded that the growth of the yeast almost ceased when the temperature was above 50℃ and could also be inhibited to some extent during the decrease of the pH to the isoelectric point 3.22.Considering the characteristics of the continuous crystallization,the reduction of residence time to avoid contamination was also investigated.Experimental results showed that when the residence time was adjusted to below 9.12h,the wild yeast could be diluted and washed out from the crystallizer.This operation reduces the loss of the main product of glutamic acid during the extraction process.