摘要
为了使酿酒废弃物酒糟得以重复利用,降低环境污染,该研究将酒糟作为发酵原料,对木醋杆菌(Acetobacter xy Linum M12)发酵产细菌纤维素进行工艺条件的优化。按照酒糟∶蒸馏水=1∶4 g/g的料液比过滤得到酒糟浸出液,并分析酒糟浸出液成分,以细菌纤维素产量为响应值,从葡萄糖、蛋白胨、酵母粉、柠檬酸、Na2HPO4·12H2O、KH2PO4·3H2O、Mg SO4·7H2O和接种量这8个影响细菌纤维素产量的因素中筛选出显著水平为95%以上的三因素,通过响应面设计对这3个因素进行响应面优化,得出产细菌纤维素数学模型的R2为0.9734,并对数学模型进行了理论分析。研究表明:影响细菌纤维素产量的三因素的影响主次顺序依次为葡萄糖、接种量、柠檬酸,产细菌纤维素的二阶回归模型(P=0.0001)高度显著,决定系数R调整2=0.9392,在此基础上得到的最优的培养基配方为:每1 L酒糟浸出液加入葡萄糖23 g,蛋白胨25 g,酵母粉25 g,柠檬酸4.5 g,Na2HPO4·12H2O 2g,KH2PO4·3H2O 1g,Mg SO4·7H2O 0.2g,接种量8%,发酵温度30°C,培养周期7 d,得到细菌纤维素的预测产量为14.42 g/L。通过验证分析在此条件下细菌纤维素产量为14.44 g/L与预测值(14.42 g/L)吻合度较高,相对误差为0.14%,比优化前(6.0 g/L)提高了140.6%,研究结果为实现酒糟的综合利用提供参考。
China is one of the biggest agriculture countries and brewing countries in the world. Distillers’ grains are the wastes produced along with brewing, they are full of nutrients but they are thrown away, which brings pollution to the environment. Bacterial cellulose （BC） is a new biomaterial and has special properties such as higher water content, higher mechanical properties. BC has broad applications in food, medicine, environmental industries. But lower productivity with higher price limits the broad application of BC. So this work considered to utilize distillers’ grains as fermentation materials of bacterial cellulose to optimize the production of BC from Acetobacter xylinum M12 by using response surface methodology. The ratio of water to distillers’ grains was 4：1 （g/g）; and filtered by eight-layer gauzes, the vinasse leaching solution was got. The composition of vinasse leaching solution was evaluated by double nitro salicylic acid （DNS） method, bradford method and high performance liquid chromatography （HPLC） method. Eight parameters including glucose, peptone, yeast powder, citric acid, Na2HPO4·12H2O, KH2PO4·3H2O, MgSO4·7H2O and size of inoculum were screened by Plackett-Burman design and 3 factors with significance level of above 95%were optimized by the response surface method using a three-level, three-factor Box-Behnken design. The data were analyzed by the software Design-Expert 8.0, and the R2 for mathematical model for BC fermentation was 0.9734. The regression equation was optimized and evaluated when the optimum conditions and interactive effects were imposed. The microstructure of BC was analyzed by fourier transform-infrared spectrum （FTIR）. The results showed that the vinasse leaching solution was full of nutrients, which contained reducing sugar 1 990 mg/L, protein 3 400 mg/L, citric acid 2 060 mg/L and succinic acid 5 638 mg/L. The order of the influence of 3 factors on BC fermentation of distillers’ grains from high to low was： glucose, size of inoculum and citric acid, the experimental data were fitted to a second-order polynomial equation using multiple regression analysis. The quadratic regression model was fitted well, as shown by the significance level of ‘total regress’ （P=0.0001）, ‘lack of fit’ being not significant （P=0.6729） and the high values of determination coefficients before and after adjusting i.e. R2=0.9734 and Radj2=0.9392. The best conditions were as follows：to per 1 L vinasse leaching solution, add 23 g glucose, 25 g peptone, 25 g yeast powder, 4.5 g citric acid, 2 g Na2HPO4·12H2O, 1 g KH2PO4·3H2O and 0.2 g MgSO4·7H2O, with inoculation amount of 8%, fermentation temperature of 30℃ and fermentation time of 7 d. Under these conditions the result of confirmatory experiment （14.44 g/L） was in good agreement with the predicted value （14.42 g/L）, and the production increased by 140.6% compared with 6.00 g/L before optimization. The results of analysis confirmed that the response model was suitable for reflecting the expected optimization, and the model was accurate and satisfactory. The FTIR analysis of BC verified the product. This study provides the reference for the resourceful use of distillers’ grains.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2015年第8期302-307,共6页
Transactions of the Chinese Society of Agricultural Engineering
基金
上海市科委地方院校能力建设项目(10540501100)
上海市联盟计划(LM201443)
关键词
细菌
纤维素
优化
酒糟
表征
bacterial
cellulose
optimization
distiller’s grains
characterization
