Effect of cultivating conditions on α-galactosidase production by a novel Aspergillus foetidus ZU-G1 strain in solid-state fermentation

The work is intended to achieve optimum culture conditions of α-galactosidase production by a mutant strain Aspergillusfoetidus ZU-G1 in solid-state fermentation (SSF). Certain fermentation parameters involving moisture content, incubation temperature, cultivation period of seed, inoculum volume, initial pH value, layers of pledget, load size of medium and period of cultivation were investigated separately. The optimal cultivating conditions of α-galactosidase production in SSF were 60%initial moisture of medium, 28 ℃ incubation temperature, 18 h cultivation period of seed, 10% inoculum volume, 5.0～6.0 initial pH of medium, 6 layers of pledget and 10 g dry matter loadage. Under the optimized cultivation conditions, the maximum α-galactosidase production was 2037.51 U/g dry matter near the 144th hour of fermentation.     

21世纪生命科学呼唤现代实验技术

21世纪堪称生命科学的世纪。实验技术是生命科学创立和发展的基石。现代生命科学呼唤与时俱进的实验技术,从而既造福于人类,又促进生命科学的发展。     

Effect of temperature on batch elastase production by Bacillus sp.EL31410

The production of elastase by Bacillus sp. EL31410 at various temperatures was investigated. In order to study the effect of temperature on elastase fermentation, different cultivation temperatures, ranging from 39 ℃ to 28 ℃, were evaluated in shake flask. The result indicated that 37 ℃ was best for cell growth at earlier stage; while maximum elastase activity was obtained when the cells were cultivated at 30 ℃. This result was verified by batch fermentation in 5-L bioreactor under 37 ℃ and 30 ℃ temperature, respectively. The specific cell growth rate at 37 ℃ was higher than that at 30 ℃ latory temperature cultivation mode were evaluated in the next study. When compared to single temperature of 37 ℃ or 30 ℃, both two-stage temperature shift strategy and oscillatory temperature strategy improved biomass but did not yield the same result as expected for elastase production. The maximum biomass (both 8.6 g/L) was achieved at 30 h at 37 ℃, but at 42 h using two-stage temperature cultivation strategy. The highest elastase production (652 U/ml) was observed at 30 ℃ in batch process. It was concluded that cultivation at constant temperature of 30 ℃ was appropriate for elastase production by Bacillus sp. EL31410.     

Batch and fed-batch production of butyric acid by clostridium butyricum ZJUCB

The production of butyric acid by Clostridium butyricum ZJUCB at various pH values was investigated. In order to study the effect of pH on cell growth, butyric acid biosynthesis and reducing sugar consumption, different cultivation pH values ranging from 6.0 to 7.5 were evaluated in 5-L bioreactor. In controlled pH batch fermentation, the optimum pH for cell growth and butyric acid production was 6.5 with a cell yield of 3.65 g/L and butyric acid yield of 12.25 g/L. Based on these results, this study then compared batch and fed-batch fermentation of butyric acid production at pH 6.5. Maximum value （16.74 g/L） of butyric acid concentration was obtained in fed-batch fermentation compared to 12.25 g/L in batch fermentation. It was concluded that cultivation under fed-batch fermentation mode could enhance butyric acid production significantly （P〈0.01） by C. butyricum ZJUCB.     

Influence of medium components on elastase production using crude sources by Bacillus sp. EL31410

A newly isolated strain EL31410, producing elastase (E.C3.4.4.7) with high elastolytic activity was identified as Bacillus sp. In the medium optimization, it was found that wheat bran and soybean flour hydrosate were the best crude carbon and nitrogen source for enzyme production, respectively. Addition of corn steep flour can affect the bacterium growth and elastase production. A fractional factorial design was applied to study the main factors that affect the enzyme production, and central composite experimental design and response surface methodology were adopted to derive a statistical model for the effect of wheat bran and soybean flour hydrosate on elastase production. The experimental results showed that wheat bran had positive effect but soybean flour hydrosate had negative effect, on enzyme production. An initial concentration of 3.4%(w/v) wheat bran and 9.4%(v/v) soybean flour hydrosate were found to be optimal for enzyme production in batch culture. The time course of elastase production in the optimized medium composition was also described.     

基于应用型人才培养需求的教学课程整合与优化

“生物反应器与发酵工程”与“生物制药设备与分离纯化技术”是我校生物技术专业学开设的两门应用型专业课程。这两门课的理论教学内容与前期基础课程存在诸多交叉重叠,导致实验课时不足和实验课教学内容连贯性差等问题,严重影响教学效果。根据近年来对这两门课程的教学实践与体会,结合两门课程所存在的问题和应用型人才培养的需求,将两门课整合为一,对理论教学内容、实验教学内容、实践教学环节以及考核方式等方面进行整合优化,提高教学质量和教学效率。     

Effect of cultivating conditions on α-galactosidase production by a novel Aspergillusfoetidus ZU-G1 strain in solid-state fermentation

The work is intended to achieve optimum culture conditions of α-galactosidase production by a mutant strain ,Aspergillusfoetidus ZU-GI in solid-state fermentation （SSF）. Certain fermentation parameters involving moisture content, incubation temperature, cultivation period of seed, inoculum volume, initial pH value, layers of pledget, load size of medium and period of cultivation were investigated separately. The optimal cultivating conditions of α-galactosidase production in SSF were 60% initial moisture of medium, 28 ℃ incubation temperature, 18^h cultivation period of seed, 10% inoculum volume, 5.0-6.0 initial pH of medium, 6 layers of pledget and 10 g dry matter loadage. Under the optimized cultivation conditions, the maximum α-galactosidase production was 2037.51 U/g dry matter near the 144th hour of fermentation.     

一种下喷式液泵型生物反应器的发酵性能研究

对具有自主创新的下喷式液泵型生物反应器进行发酵性能的研究,采用了在发酵生产和研究中经常使用的有代表性的酵母菌、霉菌与放线菌3种微生物进行产品发酵试验,并与搅拌式生物反应器作对比。结果显示,下喷式液泵型生物反应器的发酵产率明显高于搅拌式生物反应器,而能耗则只有后者的58%。     

Bacillus Megaterium在Vc二步发酵中伴生活性初步研究

在维生素C二步发酵中,Bacillusmegaterium作为伴生菌能有效促进Gluconobacteroxydans的生长和产VitaminC的前体 2 酮基 L 古龙酸(简称 2 KLG)。实验室利用低能离子对出发菌BP5 2进行诱变选育,获得一株B.megaterium突变体GB82,此突变体与G.oxydans组成的混合体系GAB,比原始混合体系 2 980产酸水平高 1 0个百分点以上。比较研究了GB82与原始B.megateriumBP5 2分泌的生物活性物质对产酸菌G.oxydans产 2 KLG的影响,据此提出此活性物质可能是某种蛋白,且此蛋白在极端条件下会部分失活的观点;并且通过RandomAmplifiedPolymorphicDNA(RAPD)分析揭示了低能离子注入造成的二者基因水平上的差异。     

谷氨酸发酵生产工艺冷凝水的利用探讨

在味精清洁生产工艺中,四效蒸发浓缩谷氨酸超滤清液,以及三效浓缩等电结晶母液,所得的蒸发凝结水（简称工艺冷凝水PCO）,因COD、氨氮稍高而不能直接排放。为解决这一环保问题并节约水资源,本文研究了将PCO作为配料水应用于味精生产以及用于部分取代超滤的清洗用水的可行性。通过与自来水进行比较,考察了其对液化、糖化和发酵过程及超滤清洗效果的影响。