【作者】 杨转琴；

【导师】 秦广雍； 李宗伟；

【作者基本信息】 郑州大学 ， 生物物理， 2010， 硕士

【摘要】 餐饮废水排放量大,污染严重,其处理逐渐成为城市生活污水处理的新重点。国内外,通过微生物发酵处理餐饮废水的技术逐渐兴起。本实验从采自屠宰场、豆制品加工厂、餐馆及学校餐厅下水道口的4个样品中分离筛选得到高效降解餐饮废水蛋白的菌株D-4,对该菌株的菌落形态、生理生化指标等方面进行了研究,初步鉴定为巨大芽孢杆菌(Bacillus megaterium)。对D-4菌株的生长曲线研究显示：0～4h该菌生长处于迟缓期,4～28h为对数增长期,28h后进入稳定期；蛋白降解曲线研究发现：降解36h时,蛋白降解率已达到81.67%。以从自然界分离筛选出的B. megaterium D-4为出发原始菌株,利用紫外照射和离子束注入诱变进行复合诱变育种,在紫外诱变时,选择照射时间为4min(存活率为17.10%)；低能离子注入时,选择能量30 keV,剂量6×1015·ion/cm2,存活率为13.40%。在该条件下对出发菌株进行复合诱变,通过初筛和复筛,选育出一株突变株D-4-29-3,其蛋白降解率比原始出发菌株D-4提高了18.20%,也大大缩短了生长周期和蛋白降解周期,经15次传代实验表明该菌株遗传稳定性良好。在菌株D-4-29-3降解条件的研究中,探讨了pH、温度、接种量、摇床转速、不同碳源及不同配比发酵培养基成分对蛋白降解率的影响。确定其降解蛋白的最优发酵培养基配比与降解的最佳工艺条件如下：蔗糖1.0%,酪蛋白1.0%,酵母膏0.2%,K2HPO4 0.3%;初始pH 7.0,种龄12h,接种量4.0%,温度32～37℃,摇床转速180 rpm/min,降解24h。在此条件下,其蛋白降解率最高可达97.56%。更多还原

【Abstract】 Restaurant wastewater has large emissions and serious pollution,the treament has gradually become the new focus of the sewage treatment of urban life.At home and abroad, the technology to deal with food wastewater through microbial fermentation gradually rises.In the experiment,protein degrading strain was isolated from four protein-contained sewage samples which were collected from slaughterhouse、bean curd manufactory、cloaca of university and restaurant.One bacterial strain D-4 for high-protein degradation was screened.Based on morphology, physiology, biochemistry analysis, this bacterial strain was preliminarily identified as Bacillus megaterium,From the growth curve and protein-degrading curve of D-4,it is showed that D-4 is in the lag phase during 0～4h,in the logarithmic phase during 4-28h and in the stationary phase after 28h;it is also showed that the rate of degradation is up to 81.67% at 36h.On the base of the original strain Bacillus megaterium D-4 from nature,was treated with UV and ion beam. In the UV mutagenesis, the exposure time was 4min (the survival rate was17.10%);and under ion beam implantion, the energy of 30keV and dose of 6×10 ion/cm2, the survival rate was 13.40%. Under these conditions, one mutant named D-4-29-3 was bred by primary screening and second screening,the protein degradation rate of was increased by 18.20%, and also the period of degreding protein and growth period were sharp shorten. The stain has good genetic stability after 15 times of subculture.In the study of protein-degrading conditions of strain D-4-29-3,we dicussed the influence on protein-degrading rate of factors pH value、temperature、inoculum size、dissolved oxygen、carbon nutriments and different ratio of fermentation medium composition. The optimum fermentation medium compositions were determined as: Sucrose 1.0%、casin 1.0%、yeast extract 0.2%、K2HPO4 0.3% and initial pH 7.0;and the better conditions of protein degradation was selected for 24h at 32～37℃on a rotary shaker(180～200r/min) incoulated by 4 percent.In these conditions,the highest rate of degrading protein could reach 97.56%.更多还原