汽爆玉米秸秆脱毒及发酵丁醇工艺的实验研究

摘要

研究了不同脱毒方法对汽爆玉米秸秆发酵产丁醇的影响及发酵工艺。实验共考查了十种不同的脱毒工艺路线，结果表明：汽爆玉米秸秆经水洗预处理脱毒后，经酶解、离心去除沉淀物，并补加营养物质是一条较佳的工艺路线。在此基础上，进一步利用单因素实验和正交实验，考察了发酵温度、pH值、接种量、菌种种龄、培养基组成、发酵时间对丁醇发酵的影响，得到较优的丁醇发酵工艺条件为，发酵温度37℃，pH7.0，接种量7%，菌种种龄27 h，培养基组成：酵母抽提物1.0 gL1、KH2PO40.8 gL1、MgSO4·7H2O 0.1 gL1、(NH4)2SO42.0 gL1、FeSO4·7H2O 0.03 gL1、尿素2.0 gL1，发酵时间48 h。在此优化条件下，发酵液中起始糖浓度为50 gL1时，丁醇的发酵浓度达到了9.42 gL1。%The effects of different detoxification methods on the fermentation process and butanol production of steam-exploded corn stalk were studied. Ten different detoxification processes were investigated respectively, the results show that the suitable method of detoxification is rinsing the steam-exploded corn stalk firstly, then enzymatic hydrolysis and removing the sediments, followed by adding nutrients finally. On this basis, the effects of process parameters, such as fermentation temperature, pH value, inoculum amount, strain age, medium compositions and fermentation time, on butanol fermentation were investigated by single-factor experiment and orthogonal tests. The optimum conditions of the fermentation process are as follows:fermentation temperature 37℃, pH value 7.0, inoculum 7%, strain age 27 h, the medium compositions are yeast extract 1 gL1, KH2PO4 0.8 gL1, MgSO4·7H2O 0.1 gL1, (NH4)2SO4 2.0 gL1, FeSO4·7H2O 0.03 gL1, urea 2.0 gL1, and fermentation time 48 h. When the initial reducing sugar concentration of the fermented liquid is 50 gL1, the concentration of the butanol can reach 9.42 gL1 under the optimum conditions.