摘要:阿魏酸酯酶又称肉桂酸酯酶，它是一种羧酸酯酶，Faulds CB和HWilliamson G于1991年在橄榄色链霉菌(Streptomycesolivochromogens)的培养物中，第一次观测到阿魏酸酯酶可以从麦麸中释放阿魏酸。从那以后，人们认识到阿魏酸酯酶是许多微生物半纤维素酶系的组成部分，到现在为止，绝大多数的阿魏酸酯酶都是从真菌中而不是细菌中被分离的，能够水解阿魏酸甲酯、低聚糖阿魏酸酯和多糖阿魏酸酯中的酯键，将阿魏酸游离出来。它还具有切断细胞壁中多糖-多糖、多糖-木质素间的交联的功能，从而有利于降解细胞壁物质中的多糖和释放木质素。阿魏酸酯酶有广泛的用途，它可以从许多工农业副产品中释放阿魏酸，这些副产品有：麦麸、玉米麸、玉米秆、酒糟、甜菜渣、燕麦壳、麦秆、咖啡渣和苹果渣等，最近，人们也越来越多关注阿魏酸酯酶在处理这些农副产品获得阿魏酸中的应用前景。
本实验从枯枝腐叶比较多的大树下的土壤中筛选得到一些产阿魏酸酯酶真菌的野生型菌株，通过严格的初筛和复筛方法获得一株高产阿魏酸酯酶真菌的菌株，再通过基因测序等一系列分子生物学手段对其进行测序，最终测出该菌株为米曲霉真菌。
鉴定出该菌株后，再对其进行发酵条件的优化，改变发酵液的温度，pH、碳源、氮源、葡萄糖、蛋白胨、装液量及接种量等，在不同的条件下测量其酶活，查看水解圈的大小情况，通过水解圈的大小来判断它的酶活高低，最后得到的结果是当发酵液中的碳源为葡萄糖，氮源为蛋白胨，pH值=7，装液量为50ml，接种量为4%，发酵温度为28℃，发酵时间为24h的时候得到的水解圈是最大的，即酶活是最高的。这就是米曲霉产阿魏酸酯酶的最佳的发酵条件。
关键词：阿魏酸酯酶；初筛；复筛；发酵；优化
Abstract:Ferulic acid esterase is also called Cinnamic acid esterase, it is a kind of carboxylesterase, Faulds CB and HWilliamson G observed that the ferulic acid esterase can release the ferulic acid from wheat bran from the culture of Streptomycesolivochromogens in 1991 for the first time . From then on, people realized that the ferulic acid esterase is the part of many microbials hemicellulase, up to now, the vast majority of ferulic acid esterase are separated from fungus instend of bacterial, it can hydrolyze the ester bond of ferulic acid methylester, feruloylated oligosaccharides and polysaccharide ferulic acid ester to make the ferulic acid free to come out. It Also has the function of cutting off the cross-link of polysaccharide-polysaccharide and polysaccharide-lignin from the cell wall, so it is advantageous to the degrade the polysaccharides and lignin from the substances of cell wall. Ferulic acid esterase has a wide range of use, it can release ferulic acid from many industrial and agricultural by-products, these by-products are: wheat bran, maize bran, corn stover, grains, sugar beet, oat hulls, wheat straw, coffee grounds and apple residue, etc. Recently, people pay more and more attention to the aspect of broad application prospects of ferulic acid esterase can release ferulic acid in handling these agricultural and sideline products.
This experiment has screend some wild type of fungus which can produce the ferulic acid esterase from the soil under the big tree where there are full of deadwood rotten leaves. We get a high production fungi that can produce ferulic acid esterase through the strict preliminary screening and affination. Then sequence it by gene sequencing and a series of molecular biology methods, ultimately to measure the strain is Aspergillus Niger fungi.
After Identifing the strain, then carry some experiments on the optimization of fermentation conditions, change the temperature of the fermented liquid, pH, carbon source, nitrogen source and glucose, peptone, fluid volume and quantity, measuring the enzyme activity in different conditions, and observe the the size of hydrolysis circles, then judge its enzyme activity level through the hydrolysis circles, Finally the result is when the fermented liquid carbon source is glucose, the nitrogen source is peptone, pH is 7, the installed capacity of 50 ml of liquid quantity is 4%, for 28 ℃ fermentation temperature, fermentation time of 24 hours the hydrolysis circle is the biggest of all . This is the best optimization of fermentation conditions for the Aspergillus Niger fungi to produce Ferulic acid esterase.
Keywords Ferulic acid esterase Primary screen Affination Fermentation Optimization
