PDF(Pubmed)
Abstract：
The production of corn generates a substantial amount of agro-industrial waste, with corncob accounting for a significant portion of this waste. In this study, we focused on utilizing corncob as a carbon source and inducer to simultaneously produce two valuable industrial enzymes, protease, and xylanase, using a recombinant strain of B. halodurans CM1. Interestingly, xylan-rich corncob not only enhanced the xylanase activity but also induced protease activity of the modified B. halodurans CM1 strain. The effect of corncob concentration on the coproduction of protease and xylanase was investigated. Corncob with 6 % concentration induced protease activity of 1020.7 U/mL and xylanase activity of 502.8 U/mL in a 7 L bioreactor under the condition of 1 vvm aeration, 250 rpm agitation, 37 °C temperature, initial pH 9.0, and 40 h incubation period. The protease produced was an alkalothermophilic enzyme whose highest activity was at pH 12 and 50 °C, and it belonged to a serine protease family. This alkalothermophilic protease\'s activity to some degree was reduced by Co2+, Mg2+, Fe2+, Zn2+, and K+, but enhanced by Ca2+ and Ni2+ (at 5 mM). The protease was stable even under the presence of a 15 % concentration of acetone, DMSO, ethanol, and isopropyl alcohol. The protease activity at 30 °C was not considerably changed by the presence of detergent, indicating excellent potential as a washing detergent additive. According to these findings, corncob has the potential to be a substrate for the coproduction of protease and xylanase, which have a wide range of industrial uses.
摘要：
玉米的生产会产生大量的农业工业废物，玉米芯占这种废物的很大一部分。在这项研究中,我们专注于利用玉米芯作为碳源和诱导剂，同时生产两种有价值的工业酶，蛋白酶，和木聚糖酶,使用B.haloduransCM1的重组菌株。有趣的是,富含木聚糖的玉米芯不仅增强了木聚糖酶活性，而且还诱导了修饰的B.haloduransCM1菌株的蛋白酶活性。研究了玉米芯浓度对蛋白酶和木聚糖酶协同生产的影响。在1vvm曝气条件下，在7L生物反应器中，浓度为6％的玉米芯诱导的蛋白酶活性为1020.7U/mL，木聚糖酶活性为502.8U/mL，250rpm搅拌,温度37°C,初始pH9.0和40小时的潜伏期。产生的蛋白酶是一种生物碱嗜热酶，其最高活性在pH12和50°C下，它属于丝氨酸蛋白酶家族。这种嗜碱热蛋白酶的活性在某种程度上被Co2+降低，Mg2+,Fe2+,Zn2+,K+,但被Ca2+和Ni2+(5mM)增强。即使在15％浓度的丙酮存在下，蛋白酶也是稳定的，DMSO,乙醇,和异丙醇。30°C时的蛋白酶活性没有因洗涤剂的存在而发生明显变化，表明作为洗涤洗涤剂添加剂的优异潜力。根据这些发现,玉米芯有可能成为蛋白酶和木聚糖酶共同生产的底物，具有广泛的工业用途。
