混合菌种发酵柑橘皮渣生产蛋白饲料的研究

发布时间：2018-05-02 11:56

  本文选题：柑橘皮渣 + 固态发酵　； 参考：《重庆大学》2016年硕士论文

【摘要】：柑橘类是世界上最常见的水果,分布广,产量大。2015年重庆柑橘种植环节的产值达到111亿元,柑橘成为当地果农的一大收入来源。目前我国对柑橘的开发利用已经从单纯的鲜果消费到带动相关柑橘加工产业发展,其中也会产生大量的柑橘皮渣。目前对于柑橘皮渣的处理目前还是以卫生填埋为主,大量皮渣严重污染环境,因此寻找一套绿色高效的处理道路势在必行。单细胞蛋白饲料主要是指通过发酵方法生产的酵母菌、细菌、霉菌及藻类等的细胞生物体。单细胞蛋白饲料的蛋白含量高,营养组分齐全,原料来源丰富,可以结合微生物发酵工程进行柑橘皮渣的资源化利用。在发酵菌种的选择上,除了发酵常用的酵母类微生物,还可以在自然腐败的柑橘皮上寻找其他安全高效的橘皮降解菌种。发酵工艺采用微生物固体发酵法,结合当地的农业副产物作为辅料,提升发酵底物的含氮量。对于主要发酵条件进行了分析和总结,并结合饲料主要指标对产物进行评价,现得到主要结论如下。(1)挑取自然腐败的柑橘皮上的微生物,接种到纤维素培养基和果胶培养基上选择性培养,经多次分离纯化后得到纤维素降解菌和果胶降解菌。对得到菌株DNA测序比对,得到了F78产碱菌、G3-6-20抗辐射菌、F-10米曲霉菌、BC361橙黄色大理石雕菌、58289水稻恶苗病菌、K801康宁木霉菌。其中米曲霉和康宁木霉具有安全高效的特点,因此选择为发酵实验的主要原料分解菌种。(2)对米曲霉、康宁木霉,与发酵常用的酵母类菌种热带假丝酵母、球拟圆酵母进行了菌种组合研究,确定米曲霉/康宁木霉/热带假丝酵母三菌种比例为1:2:2时进行混合发酵时的麸皮组粗蛋白最高,达到32.79%,比例为1:1:1或者1:2:2时豆饼组粗蛋白最高,均达到33%以上。(3)本次混合菌种发酵实验研究的最佳发酵条件为:发酵时间84h,发酵温度33℃,含水率70%,辅料投加比例5%,菌液投加量0.4ml/g。(4)通过光照发酵和遮光发酵的对比试验,发现光照可作为一个显著的生长刺激条件(P=0.05),可以对产物的粗蛋白含量产生8%左右的相对提升。(5)对比本次研究选择的饲料标准《GB\T 5916-2008产蛋后备鸡、产蛋鸡、肉用仔鸡配合饲料》,麸皮组发酵后产物粗蛋白为30.95%;豆饼组为32.36%,远高于标准规定的20%;产物灰分均不超过4%,满足标准规定的8%。可溶性蛋白也达到了发酵前的6倍左右,丰富的可溶性蛋白含量利于饲用动物的消化吸收。
[Abstract]:Citrus is the most common fruit in the world with wide distribution and large yield. In 2015, the output value of citrus cultivation in Chongqing reached 11.1 billion yuan, and citrus became a major source of income for local fruit farmers. At present, the development and utilization of citrus in China has changed from pure fresh fruit consumption to promoting the development of related citrus processing industry, among which a large amount of citrus peel residue will be produced. At present, the treatment of citrus peel residue is mainly sanitary landfill, a large number of residue seriously pollute the environment, so it is imperative to find a set of green and efficient treatment road. Single cell protein feed mainly refers to yeast, bacteria, mold and algae produced by fermentation. The single cell protein feed has high protein content, complete nutrient components and abundant raw materials, which can be used for the utilization of citrus peel dregs in combination with microbial fermentation engineering. In the selection of fermentative bacteria, in addition to the yeast microbes commonly used in fermentation, we can also look for other safe and efficient citrus peel degradation bacteria on naturally decayed citrus peel. The fermentation process used microorganism solid fermentation method, combined with local agricultural by-products as auxiliary materials, to enhance the fermentation substrate nitrogen content. The main fermentation conditions were analyzed and summarized, and the main indexes of feed were used to evaluate the products. The main conclusions were as follows: 1) picking up the microorganisms from naturally decayed citrus peel. Cellulose degrading bacteria and pectin degrading bacteria were obtained by inoculation on cellulose medium and pectin medium. Compared with the DNA sequencing of the obtained strain, a radiation-resistant fungus, F -10 Aspergillus orangensis BC361, BC361, BC361, was obtained, and Trichoderma kangning K801 was obtained. Among them, Aspergillus oryzae and Trichoderma kangningensis have the characteristics of safety and efficiency, so they are selected as the main raw materials of the fermentation experiment, I. e., the decomposing strain of Trichoderma oryzae, Trichoderma kangningensis, and the yeast species Candida tropicalis, which are commonly used for fermentation. The strain combination study of P. oryzae showed that when the ratio of Aspergillus oryzae / Trichoderma oryzae / Candida tropicalis was 1:2:2, the crude protein of bran group was the highest, reaching 32.79%, and the proportion of crude protein of soybean cake group was the highest at 1:1:1 or 1:2:2. The optimum fermentation conditions were as follows: fermentation time 84 h, fermentation temperature 33 鈩，

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