纤维素分解菌与乳酸菌复合发酵条件的响应曲面优化分析

摘要

为给今后复合发酵添加剂的开发提供新的途径,研究了纤维素分解菌与乳酸菌复合发酵情况下二者数量均达到最优值的发酵剂量.采用响应曲面设计法,设计乳酸菌(LAB)和真菌的数量为响应值,求出响应值均为最大时的自变量值.自变量为同、异型发酵LAB和纤维素分解菌添加比例及添加剂量,其中同型[植物乳杆菌(Lactobacillus plantarum)+戊糖片球菌(Pediococcus acidilactici)]、异型[布氏乳杆菌(Lactobacillus buchneri)]发酵LAB的添加量均为1×105、3×105和5×105 cfu·g-1(即5、5.48、5.70 lg cfu·g-1),纤维素分解菌的比例为黑曲霉(Aspergillus niger)∶绿色木霉菌(Trichoderma viride)∶枯草芽孢杆菌(Bacillus subtilis)=1∶1∶2、1∶2∶1和2∶1∶1,纤维素分解菌的添加剂量为0.1％、0.2％和0.3％.LAB和真菌的数量的测定采用传统菌种计数法计数.结果表明:建立的LAB和真菌数量的二次多项式模型显著性分别为P＜O.01和P=0.03,R2分别为0.95和0.74.其中同、异型发酵LAB的添加量及其交互作用对LAB数量的曲面效应影响显著(P＜0.05).真菌的添加量以及同、异型发酵LAB的交互作用对真菌数量的曲面效应影响显著(P＜0.05).最终优化结果为同型发酵LAB添加量为5×103 cfu·g-1(5.70 tg cfu·g-1),异型发酵LAB添加量为4.7×103 cfu·g-1 (5.67 lg cfu·g-1),纤维素分解菌比例为2∶1∶1,添加量为0.3％.%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 heterofermentative 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 ％.