乳酸菌对不同起始糖浓度甘蔗渣发酵品质的影响

Effects of lactic acid bacteria on fermentation characteristics of bagasse with different soluble sugar concentrations

为有效利用废弃甘蔗渣,以微生物发酵来加快其转化,将甘蔗渣的起始含糖质量分数设置为2%、3%、4%、5%、6%和7%,以接种乳酸菌复合系LBC-8作为接菌组,接种灭菌培养基作为对照组,研究了不同起始含糖质量分数的甘蔗渣在这2种情况下发酵参数的变化及微生物多样性。结果表明:在整个发酵过程中接菌组pH较对照组下降更明显,在发酵20 d后,起始糖质量分数越高的处理,pH越低,最低为3.3;接菌组在糖质量分数为5%以上时产乳酸明显,气味酸香,质地松软,感官品质较好;含糖质量分数为5%时可溶性糖、粗蛋白、粗纤维和粗灰分质量分数分别为1.93%、2.26%、41.10%和4.43%。而对照组产丁酸明显,产乳酸较少,发酵品质较差。变性梯度凝胶电泳结果显示:接种组在起始含糖5%以上时乳酸菌优势条带较多,而对照组各质量分数的乳酸菌条带都较少。综合以上结果分析得出:当甘蔗渣起始含糖达到5%以上时,接种乳酸菌复合系LBC-8对甘蔗渣进行发酵,可以获得较好发酵品质的饲料。

It aimed to utilize bagasse and fasten its conversion into feed through bagasse fermentation.Sucrose was used to adjust the initial water-soluble carbohydrate content（WSC） to 2%,3%,4%,5%,6%,and 7%（w）.And a lactic acid bacteria community LBC-8 was inoculated into the bagasse as the inoculation group.The treatments with only the sterile MRS broth were used as the control group.During the fermentation,bio-chemical parameters and microbial diversities were analyzed.The result showed that after 20 d fermentation,the pH values of the inoculation group were lower than that of the control group,and the trends of pH falling were related to the initial WSC content,the lowermost pH value of the inoculation group was 3.3.There were significant lactic acid produced and better appearance quality when initial WSC content was above 5% in the inoculated group.The WSC,crude protein,crude fiber,crude ash contents were 1.93%,2.26%,41.1% and 4.43% separately when the WSC content was 5% after 20 d fermentation.From the patterns of denaturing gradient gel electrophoresis（DGGE）,after inoculation,the bacteria of LBC-8 rapidly became the advantageous species in the inoculated group when initial WSC content was above 5%.In the contrast,the advantageous bands were less in the control group.Comprehensive results showed that the bagasse fermented feed with good fermentation quality was obtained when the lactic acid bacteria community LBC-8 was inoculated into the bagasse with initial WSC content of above 5%.