三菌复合发酵提高厨余真蛋白含量的研究

Study on improving true protein content of food waste by combined fermentation with three strains

为改善厨余发酵的品质,增加发酵后产品蛋白含量。采用三菌复合对厨余进行发酵,探讨了三菌复合的比例、接种量、发酵时间、初始pH值对发酵效果的影响,采用L9(34)正交实验对发酵条件进行优化,并对实验菌Lc和Ydy进行16S rRNA及18S rRNA分子鉴定。结果表明,最佳发酵条件为:菌剂配比(Lc∶Ydy∶S1)为3∶2∶1,接种量为0.15%,初始pH值为5.0,发酵时间为48 h。扩大实验结果表明,在最优发酵条件下,厨余经发酵后品质得到改善,真蛋白含量由发酵前的15.42%上升到发酵后的22.47%,增加率为45.80%;发酵后大肠菌群下降到30 cfu/g以下;乳酸菌及酵母菌数量分别为1.5×109 cfu/g和6.6×108 cfu/g。分子测序及鉴定结果表明,Lc为乳酸乳球菌,Ydy为热带假丝酵母菌。

For the purpose of improving the fermentation quality of food waste and increasing the true protein content of the fermentation products,food waste was fermented by three-combined strains.Mixture ratio of these strains,inoculums concentration,fermentation time,coupled with the initial pH value were investigated by single factor experiment and orthogonal L9（34） test in this paper.Lc and Ydy were identified with the method of 16S rRNA and 18S rRNA.Results showed that the optimal fermentation conditions were as follows,mixture ratio of strains（Lc∶Ydy∶S1） of 3∶2∶1 and 0.15% inoculum concentration under the initial pH value of 5.0 for 48 hours fermentation.Furthermore,expanding experiment indicated that the quality of food waste was improved by fermentation under the optimal fermentation conditions.The content of true protein increased by 45.8% from 15.42% to 22.47%.The amount of E.coli decreased to 30 cfu/g after fermentation;the population of Lactobacillus and yeast were 1.5×109 cfu/g and 6.6×108 cfu/g,respectively.The molecular identification of the strains showed that Lc was Lactococcus lactis and Ydy was Candida tropicalis.