Condition of fermentation combined with cellulose decomposing and lactic acid bacteria based on the response surface method

The aim of this study was to investigate the fermentation dose at which the optimum fermentation amount can be met with a combination of cellulose decomposing bacteria and lactic acid bacteria, and to provide a new method for the future development of compound fermentation additives. The response surface method was used in the experiment. The number of lactic acid bacteria (LAB) and fungi were calculated as the response values, with which the maximum values of the independent variables were obtained. The independent variables included the doses and proportions of homo- and hetero-fermentative LAB and cellulose decomposing bacteria. Among them, the addition amounts of homo- (Lactobacillus plantarum and Pediococcus acidilactici) and hetero-fermentative (Lactobacillus buchneri) LAB were 1×105, 3×105, and 5×105 cfu·g-1(as 5, 5.48, 5.70 lg cfu·g-1), respectively. The tested ratios of cellulose decomposing bacteria Aspergillus niger:Trichoderma viride:Bacillus subtilis were 1:1:2, 1:2:1, and 2:1:1. The amount of cellulose decomposing bacteria was 0.1%, 0.2%, and 0.3%. The numbers of LAB and fungi were counted using the traditional bacterial count method. The results showed that the significances in the quadratic polynomial models of LAB and fungi were P<0.01 (R2=0.95) and P=0.03 (R2=0.74), respectively. The addition numbers of the homo- and hetero-fermentative LAB and their interactions had a significant effect on quantity of the affected surface of LAB (P<0.05). The addition number of fungi and the interaction of the homo- and hetero-fermentative LAB had a significant effect on the quantity of the affected surface of fungi (P<0.05). The conclusion is that the addition number of homo-fermentative LAB was 5×105 cfu·g-1(as 5.48 lg cfu·g-1), and hetero-fermentative LAB was 4.7×105 cfu·g-1(as 5.67 lg cfu·g-1), the ratio of cellulose decomposing bacteria was 2:1:1, and the addition amount was 0.3%.