Screening of inhibitors from hydrolysate of distiller's grains and its effect on butanol fermentation
Distillers'grain can be used as excellent raw material for butanol fermentation after enzymatic hydrolysis.However,the inhibitors in distillers'grain hydrolysate would affect butanol fermentation.In this paper,the main components of distillers'grain hydrolysate was detoxified by Ca(OH)2 and analyzed by GC-MS,and the main types of inhibitory substances were analyzed by multivariate statistical analysis.As a result,a total of 18 compounds were detected in distillers'grain hydrolysate,with the highest contents of acids and esters of 232.81 mg/L and 126.69 mg/L,respectively.The removal rate of acids and esters was the highest with Ca(OH)2 detoxification treatments,reaching 38.2％-78.9％and 83.1％-93.3％,respectively.and the optimal detoxification condition was pH 10,temperature 25,time 1 h.Combined with principal component analysis(PCA)and partial least-squares(PLS)analysis results,it was found that ethyl oleic acid,ethyl linoleic acid,ethyl palmitic acid,palmitic acid and hexanoic acid were the negatively signifi-cantly correlated factors that affecting the butanol fermentation.The results of single factor experiment for potential inhibitors showed that the addi-tion of 800 mg/L hexanoic acid had an inhibitory effect on butanol fermentation(P＜0.05),and the other four substances had no significant effect on it(P＞0.05).When the five substances(equal mixed)were added to 400 mg/L,the butanol fermentation was synergistically inhibited(P＜0.05),and the butanol concentration was reduced by 29.1％compared with the control group.In summary,two acids and three esters were potential inhibitors in distillers'grain hydrolysate,which synergistically inhibited butanol fermentation.
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万方数据
维普
