混菌发酵竹笋壳产单细胞蛋白培养基及发酵条件的研究

RESEARCH ON CULTURE MEDIUM OF SINGLE CELL PROTEIN PRODUCED FROM BAMBOO SHELL BY MIXED FERMENTATION AND ITS FERMENTATION CONDITION

为提高生物质利用率,探索新型饲料资源,采用Plackett-Burman设计对影响黑曲霉、产朊假丝酵母混合发酵竹笋壳产SCP的培养基组分进行评估.结果表明:影响发酵粗蛋白产量的关键因素有麦麸、尿素、初始含水量、温度、时间和接种量.在此基础上,采用响应曲面法分别对发酵培养基组成和发酵条件进行优化,获得最佳发酵方案(以100 g干物质计)为:竹笋壳粉78 g、葡萄糖1 g、麦麸20.3 g、NaNO_3 0.3 g、KH_2PO_4 0.15 g、MgSO_4·7H_2O 0.2 g、FeSO_4·7H_2O0.001 g,初始含水量为68 mL,pH自然;黑曲霉接种量(W/W)为12%,单菌发酵温度为28℃,培养48 h后以36%(V/W)接种量接入产朊假丝酵母,31℃下混合发酵56 h.验证试验表明,粗蛋白最大含量为12.85%,与预测值12.80%较接近,比优化前提高52.6%.

In order to improve utilization of biomass and find new feed resources,we adopted Plackett-Burman design to evaluate medium components influencing single cell protein（SCP） produced from bamboo shell by mixed fermentation using the mixture of Aspergillus niger and Candida ulilis.The results showed thai the key factors influencing the yield of crude protein included wheat bran,urea,initial water content,temperature, incubation time and inoculation amount.In addition,we also adopted response surface methodology to optimize the medium composition and the fermentation conditions,and the optimum formula was as follows,calculated by 100 g dry matters：bamboo shell 78 g,glucose 1 g,wheat bran 20.3 g,NaNO_3 0.3 g,KH_2PO_4 0.15 g, MgSO_4＊7H_2O 0.2 g,FeSO_4＊7H_2O 0.001 g,and initial water content 68 mL.The fermentation process included the following steps;incubating Aspergillus niger 12%（W/W）,fermenting at 28℃for 48 hours,incubating Candida utilis 36%（V/W）,and mixed fermenting at 3：℃for 56 hours.Tests showed the maximum content of crude protein was 12.85,which was close to the prediction value 12.80%and was improved by 62.6%in comparison to that before optimization.