羽毛降解菌的筛

发布时间：2018-01-11 05:28

本文关键词：羽毛降解菌的筛选、发酵条件优化及降解特性研究　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：羽毛是禽类加工过程中产生的一种副产物,含有丰富的蛋白资源。因为降解缓慢,利用率低,每年产生的大量羽毛成为废弃物,造成环境污染。微生物降解羽毛既可保护环境又实现废物的资源化利用,具有显著的社会效益和经济效益。本论文从土壤中筛选分离出一株高效降解羽毛的菌株,鉴定了筛选菌种属、研究了发酵条件对菌株降解羽毛产可溶蛋白的影响,以及羽毛在降解过程中的特性,为羽毛发酵产物的进一步应用提供理论基础。论文得到以下研究结论:1、从4处来源不同的土壤中,经过初筛、复筛筛选出一株降解羽毛效果较好的菌株,命名为H3。对H3菌株进行形态学观察、生理生化实验及16S rRNA基因鉴定,鉴定菌株H3为蜡状芽孢杆菌的一种,命名为蜡状芽孢杆菌H3(Bacillus cereus H3),并构建了系统发育树。基因序列提交到NCBI,登录号为KX548899。2、以鸡毛作为培养基唯一碳源,通过单因素实验、PB试验及Box-Behnken响应面设计对培养基组成和发酵条件进行了优化,确定了Bacillus cereus H3降解羽毛产可溶蛋白最优的发酵工艺为:(1)培养基:羽毛含量20 g/L、无机盐NaCl0.1g/L、MgSO4 0.1 g/L及KH2PO4/K2HPO4为0.7/1.4 g/L;(2)发酵条件:装液量50 mL/250 mL、接种量3%、初始pH值10.5及培养温度31℃。发酵产可溶蛋白含量较优化前提高了4.8倍。3、在优化发酵条件下,研究了菌株Bacillus cereus H3降解羽毛的特性。发酵产生的可溶蛋白浓度和角蛋白酶活力在同一时间达到最大值;氨基酸含量在发酵6天后达到最大值,发酵液含有4种必需氨基酸,其中含量最高的氨基酸为苯丙氨酸;抗氧化实验表明羽毛发酵液具有良好的抗氧化性;红外分析结果表明发酵水解物的组成含有多肽结构;扫描电镜观察完整鸡毛在降解过程中的微观结构,结果表明羽毛的羽枝首先降解,之后羽轴会逐渐被降解。
[Abstract]:Feather is a by-product of poultry processing, rich in protein resources. Because of the slow degradation, low utilization rate, a large number of feather every year have become waste, causing environmental pollution. Microbial degradation of feathers can protect the environment and realize the resources utilization of waste, has significant social benefits and economic benefits. This paper screened from soil isolated strains of feather degrading bacteria, screening and identification, study the effects of fermentation conditions on the degradation of feather production of soluble protein, and the characteristics of feathers in the degradation process, provide the theoretical basis for the further application of the feather fermentation products. This paper obtained the following conclusions: 1 and from 4 different sources of soil, after screening, screening were screened better feather degrading strains, named H3. was used to observe the morphology of H3 strain, physiological and biochemical experiments 16S and rRNA gene identification, strain H3 was identified as Bacillus cereus, named Bacillus cereus H3 (Bacillus cereus H3), and the phylogenetic tree. The gene sequence was submitted to NCBI, the accession number is KX548899.2, with the feather as a medium sole carbon source, through the single factor experiment, PB Box-Behnken test and response surface design were used to optimize the medium composition and fermentation conditions, determine the Bacillus cereus H3 production of soluble protein degradation of feather optimal fermentation process was as follows: (1) culture medium: Feather content 20 g/L, inorganic salt NaCl0.1g/L, MgSO4 0.1 g/L and KH2PO4/K2HPO4 0.7/1.4 g/L; (2) fermentation conditions: liquid volume 50 mL/250 mL, 3% inoculation quantity, initial pH value 10.5 and incubation temperature of 31 DEG C fermentation. The content of soluble protein was 4.8 times higher than in the.3 before optimization, optimization of fermentation conditions, characteristics of the strain Bacillus cereus H3 feather degrading fermentation. The soluble protein concentration and keratinase activity reached maximum at the same time; amino acid content reached the maximum in 6 days after fermentation, the fermentation liquid containing 4 kinds of essential amino acids, the amino acid content was the highest in phenylalanine; antioxidant experiments showed that feather fermentation liquid has a good oxidation resistance; infrared analysis showed that the composition of fermentation of hydrolysate the structure of microstructures containing peptides; in the degradation process of complete feather scanning electron microscope. The results show that feather rachis branches degraded first, after will be degraded gradually.

【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TS251.92;TQ920.1

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