摘要
从采集的土壤中分离得到一株高产木聚糖酶的菌株JF8,对该菌株的菌落形态、分生孢子梗及瓶梗着生方式和分生孢子大小等形态学特征进行观察。结果发现,该菌株与棘胞木霉(Trichoderma asperellum)的形态特征极为相似,初步鉴定该菌株为棘胞木霉。进一步对该菌株的rDNA-ITS序列进行克隆并测序,利用DNAstar软件中的ClustalV法建立与该菌株ITS序列同源性较高的木霉属不同种间的系统发育树,发现该菌株的ITS序列与Genebank中已报道的棘胞木霉的ITS序列的同源性高达99.6%,结合形态特征观察结果,证实该菌株为棘胞木霉。以蔗渣和麸皮为基质,先对影响该菌株产木聚糖酶的单个因素进行研究,而后采用L9(34)正交实验对各因素对产酶影响大小进行分析。结果表明,4种因素对产酶影响从大到小依次是温度、湿度、初始pH和麸皮添加比例,最佳发酵产酶组合为:培养温度28℃,水分添加量12.5mL,初始pH值3,麸皮添加比例30%。在此优化条件下静止培养72h,菌株产酶活力可达5021.1U·g-1干曲。
Xylanase is a kind of glucosidase with the ability to hydrolyze β-1, 4 bond of xylanases in an endo-manner, whose hydrolysate are mostly dimmer and oligomer of xylose, as well as some xylose and arabinose. More attention has been paid in the last decades to the application of xylanase in saccharification of lignocellulosics, pulp and paper industry, feed industry, xylooligosaccharide preparation and brewing industry. A xylanase-producing strain named JF8 was isolated from the soil sampled from the Jiangfeng Mountain. The strain was cultured on the PDA medium and its mycelium was white at first, and then became green after 48 hours of culture. This strain was found to be similar to Trichoderma asperellum based on its morphologic characteristics such as colony, conidiophores, phialides and conidia. The Internal Tran scribed Spacer（ITS） sequence of the rDNA of the strain JF8 was amplified, and compared with that of T. asperellum. The results showed that these two strains exhibited 99.6% similarity in ITS sequence of rDNA. The strain JF8 was hence identified as T. asperellum. Bagasse and wheat bran were used as mediums to study the optimum solid fermentation conditions for the strain JF8. Experiments revealed that the strain JF8 grew best on a culture medium consisting of 3.5 g bagasse, 1.5 g wheat bran and 15 mL H2O. Under the optimum conditions, the strain JF8 had a high xylanase activity of upto 5 021.1 U·g^-1dry medium when cultured at 28 ℃ for 3 days. All studies showed that this xylanase has a good prospect for its application in industry.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2008年第5期2086-2090,共5页
Journal of Agro-Environment Science
基金
科技部"国家科技基础条件平台建设资助项目"(2005DKA21201-18)
科技部社会公益研究专项(2005DIB4J043)
关键词
棘胞木霉
ITS
固态发酵
木聚糖酶
Trichoderma asperellum
Internal Transcribed Spacer（ITS）
solid fermentation
xylanase
作者简介
袁宏伟（1982-），男，硕士，主要从事应用微生物方面的研究。E-mail：yuananbang@163．com
通讯作者：黄俊生E-mail：H888111@126．com
