硕士论文-微生物菌剂的规模化培养技术.pdf

天津大学
硕士学位论文
微生物菌剂的规模化培养技术
姓名:常素云
申请学位级别:硕士
专业:环境工程
指导教师:孙井梅
20070601
中文摘要
微生物菌剂规模化培养技术的研究,是投菌法改善外环河水质项
目研究中的一部分。投菌法在实际应用中需要大量的菌剂,因此本项
研究的目的是研究菌剂的规模化生产方法,以保证投菌法在实际应用
中对菌剂的需要。本文以降低微生物菌剂生产成本为出发点,研究模
拟啤酒废水培养微生物菌剂的可行性,并以酵母菌为例,研究了适宜
规模化生产的碳源及氮源。考虑到下游加工的需要,进一步研究了高
密度培养方法。由于传统发酵罐价格昂贵,实际应用中基建费用较高,
因此研究新型生物反应器-气升式反应器代替传统发酵罐
通过传统培养基与模拟啤酒废水培养基比较,得出除絮凝剂产生
菌外,其它七种菌在模拟啤酒废水中的生长量均大于或者等于传统培
养基,说明模拟啤酒废作为培养基培养这七种菌是可行的。将玉米淀
粉糖化液、玉米浆分别与常用碳源(葡萄糖)、氮源(酵母膏)对比,
得出糖化液、玉米浆中生长的酵母菌浓度较高,且菌液对原水的 COD
去除率较高,说明以玉米淀粉糖化液、玉米浆作为酵母菌规模化生产
碳源及氮源是可行的。在此基础上,利用正交实验原理并结合酵母菌
对原水的CODa去除率,确定了酵母菌分批培养的优化培养基为:模
拟啤酒废水1L、糖化液5ml、玉米浆9g:最佳培养条件为:接种
量15%、装液量100ml250ml、起始pH4.5、培养温度30℃、摇床
转速220r/min。通过补料培养与循环培养两种高密度培养方案比较得
出:在现有实验条件下,循环培养的最终菌体浓度较高,且操作简单,
因此选择循环培养作为酵母菌的高密度培养方法。并结合循环培养过
程中酵母菌的降解能力变化,得出酵母菌的最佳循环培养次数为三
次。在烧瓶实验的基础上,研究设计新型生物反应器气升式反应器
在微生物培养中的应用,并通过实验确定最佳通气量为0.25vm。将
气升式反应器与循环培养方法相结合,酵母菌最终浓度可达53.7gL。
综合上述研究成果,拟设计了实际生产工艺流程。在此基础上,进行
了经济效益评价。培养基成本为1.7元/千克菌体,气升式反应器运行
成本为5.31元/千克菌体干重
关键词:微生物菌剂规模化培养高密度循环培养气升式反应器
ABSTTRACT
Research on mass cultivation of microorganism was performed as a part of the
study on the microorganism addition to improve the contaminated water quality of
Wai Huan River. Large quantity of microorganisms are needed in practical application
so mass cultivation of microorganism was performed to reduce the costs of
microorganism cultivation. The feasibility of simulate beer wastewater used as culture
medium was investigated. The carbon and nitrogen sources for mass cultivation of
yeast was explored and selected. To satisfy the downstream processing, a high density
cultivation is required. An airlift bioreactor was designed to take place of the
expensive traditional digesting tank
Compared with the traditional culture medium, the simulate beer wastewater
culture medium is better for microoganism growth. it was found that: simulating beer
wastewater can be used to culture microorganisms, except for microbial
flocculant-producing bacteria. Study on the feasibility of corn saccharification liquid
and com steep liquor as carbon and nitrogen source of yeast cultivation was also
performed, by comparing with the traditional ones. Higher density yeast and greater
degradation rate are achieved in the investigated culture medium. On that basis.
optimum program of yeast cultivation was achieved, on the orthogonal experiment
principle and considering the wastewater removal rate(CODE). The optimum medium
is one litter of simulating beer wastewater, five milliliters of saccharification, and nine
grams of corn steep liquor. The optimum culture condition was carried out by
taking100 milliliters to the conical flask of 250 milliliters, before inoculating 15
milliliters of inoculum in it, with the culture medium PH on4.5, 30C in cultivation
temperature and 220 r/min on shaking speed. After comparing with the fed-batch
cultivation, Cyc-cultivation method was adopted to achieve high density cells. From
the high density experiment, it was found that: the three times cyc-cultivation have the
greatest degradation rate. On the basis of flask experiment, the designed airlift
ioreactor experiments are carried through. The validation results show the method is
satisfied and the o