土壤中单宁和植酸降解菌的筛选、鉴定及液态发酵研究  

Screening and identification of tannic acid and phytic acid degradative microorganisms from soil and the submerged fermentation study

作　　者：王晓东[1] 胡海滨[1] 麦康森[1] 张彦娇[1] 徐玮[1] 艾庆辉[1] 张文兵[1] 

机构地区：[1]中国海洋大学农业部水产动物营养与饲料重点实验室,教育部海水养殖重点实验室,山东青岛266003

出　　处：《水产学报》2016年第10期1634-1642,共9页Journal of Fisheries of China

基　　金：教育部博士点专项基金(20120132120025);山东省优秀中青年科学家科研奖励基金计划(BS2013SW007);国家自然科学基金课题(31202006)

摘　　要：为从土壤中筛选能够同时降解单宁和植酸的微生物,本实验利用富集培养技术,分离、筛选、鉴定土壤中的单宁和植酸降解菌,并研究其在液态发酵下的产酶能力。结果显示,从土壤中共获得109株纯菌落,包括39株细菌、46株酵母菌以及24株霉菌。分别用单宁筛选性培养基和植酸筛选性培养基筛选上述菌株,获得27株植酸降解菌和14株单宁降解菌,其中霉菌M-6、M-3和M-1可以同时分解单宁和植酸,且霉菌M-6的水解圈直径大于M-3和M-1。在液态发酵条件下,随着发酵温度的升高(20~35°C),霉菌M-6产单宁酶和植酸酶的活力呈现先升高而后降低的趋势,在发酵温度为30°C时达到最高值(P<0.05)。随着发酵p H的升高(p H 4~7),霉菌M-6产单宁酶和植酸酶的活力呈先升高后降低的趋势(P<0.05);其中单宁酶活力在发酵p H值为5时达到最高值,显著高于其他处理组(P<0.05);而植酸酶活力在发酵p H值为5时达到最高值,显著高于发酵p H 4和7处理组(P<0.05),但与发酵p H 6处理组差异不显著(P>0.05)。通过菌落和菌株形态学以及分子测序方法,鉴定M-6为黑曲霉。因此,本研究从土壤中分离筛选出3株(M-6、M-3和M-1)能够同时水解单宁和植酸的降解菌,在液态发酵条件下,黑曲霉M-6产单宁酶和植酸酶的最佳发酵温度为30°C,最佳发酵p H值为5。Tannic acid and phytic acid are two important anti-nutritional factors that limit the utilization of plant ingredients in aqua-feed industry. Enrichment-culture technique was used to isolate, screen and identify the efficient microorganisms from soil which could degrade both tannic acid and phytic acid. In this study, 109 microorganisms were isolated, of which 27 isolates could degrade phytic acid and 14 isolates exhibited tannic acid degradation potential. Among these isolates, fungi M-6, M-3 and M-1 degraded both tannic acid and phytic acid,of which fungus M-6 possessed higher degradative capacity than fungi M-3 and M-1. With the increase of fermentative temperature（20 °C^35 °C）, the activities of tannase and phylase produced by fungus M-6 in submerged fermentation both showed a firstly-increase-and-then-decrease trend, with the highest activities observed at 30 °C（P〈0.05）. With the increase of fermentative p H（4~7）, the activities of tannase and phylase of fungus M-6 in submerged fermentation both firstly increased and then decreased（P〈0.05）. The activity of tannase from p H 5 treatment was significantly higher than other groups（P〈0.05）, the activity of phylase from p H 5 group was significantly higher than p H 4 and 7 groups（P〈0.05）, but the difference was not significant compared with p H6（P〈0.05）. The isolate fungus M-6 was characterized as Aspergillus niger, supported by the morphologic taxonomy as well as the sequences of the ITS1-5.8S-ITS2 ribosomal DNA region. Therefore, fungi M-6, M-3 and M-1 could degrade both tannic acid and phytic acid. The optimum fermentative temperature for fungus M-6 was30 °C and the optimum fermentative p H was 5, under submerged fermentation.

关 键 词：降解微生物 水产饲料 单宁 植酸 液态发酵 

分 类 号：S917.4[农业科学—水产科学]