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衣康酸产生菌的分离和选育 总被引:3,自引:0,他引:3
本文叙述了从土壤分离衣康酸产生菌的过程和方法,使用Co60与UV-高温复合处理土曲霉野生菌株,获得一些突变体(Mo.82-r17、No.25一13B、No.25—23B and No.25-24B),用正交试验确定较佳培养基组成,在37℃下摇瓶培养No.82一r17,培养液积累衣康酸3.5g/100ml,对供给糖转化率35%,从培养液回收衣康酸与标准衣康酸进行红外光谱测定,比较两者吸收曲线,确证它是衣康酸。 相似文献
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用多种诱变法对衣康酸产生菌原始菌株进行诱变,得到高产菌株16株,采用“正交试验-中心试验-正交试验”的策略优化培养基,对影响衣康酸生产的原料、水质等进行了研究。所得高产菌株生产适应性强,产酸水平为65g/100ml,残还原糖小于01g/100ml,摇床发酵周期小于96h,500L发酵罐发酵周期小于70h。 相似文献
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紫外线诱变豇豆根瘤病512的研究 总被引:3,自引:1,他引:2
将活化后的豇豆根瘤菌512(R.Ieguminosarm512)涂抹于含有1g/L琥珀酸钠和0.8%蛋白胨的YEM固体培养基上,然后以紫外线照射,从中选出合成IAA能力较高和抗性较强的突变菌株。测定结果表明,该菌株合成IAA成力比原出发菌株高一倍左右。其合成IAA能力与照射剂量、照射次数和培养基中蛋白胨的浓度有关。不仅如此,该突变菌株的耐碱和耐盐能力有明显提高。 相似文献
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具有ACC脱氨酶活性的细菌的分离和鉴定 总被引:3,自引:0,他引:3
在以ACC(α-氨基环丙烷梭酸)为唯一氮源的选择性培养基上,对土壤来源的细菌菌株进行了筛选。通过生长测定、对ACC降解的分析,确定了菌株ACC脱氨酶的活性,并对菌株进行了系统鉴定。 相似文献
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肌苷产生菌中降低核苷水解酶的研究 总被引:2,自引:0,他引:2
本研究以枯草杆菌肌苷产生菌SD9401(Adeˉ+Thiˉ+Hisˉ+8—AGr+6-MPr)为出发菌株,经紫外线和硫酸二乙酯诱变,在以肌苷为唯一碳源的补充培养基上筛选到一株核苷水解酶缺失菌株。实验结果表明这一突变株积累比亲株高30%左右的肌苷,平均达到26.89mg/ml,最高到28.03mg/ml。且发酵液中未测出次黄嘌呤。 相似文献
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PGDH^L生化突变型谷氨酸生产菌株选育的生化模式 总被引:2,自引:0,他引:2
以Tbm-3(icl^-,异柠檬酸裂解酶活力的生化突变株)为出发菌株,经紫外一诱变,通过依据生人代谢所设计的选择培养基(L-阿拉伯糖平板与D-葡萄糖酸钠平板)对接的筛选方法,获得磷酸葡萄糖酸脱氢酶(PGDH,E.C.4.2.1.12)忖突变型的生化突变型菌株Tbm3.18,该菌株经摇瓶发酵试验显示,比出发菌株Tbm-3提高产酸率8.9%和转化率8.1%,表明pgdh或pgdh生在变型菌株的选育,对 相似文献
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Kim-Ngan T. Tran Sivachandran Somasundaram Gyeong Tae Eom Soon Ho Hong 《Biotechnology progress》2019,35(3):e2799
Itaconic acid, which is a promising organic acid in synthetic polymers and some base-material production, has been produced by Aspergillus terreus fermentation at a high cost. The recombinant Escherichia coli that contained the cadA gene from A. terreus can produce itaconic acid but with low yield. By introducing the protein–protein scaffold between citrate synthesis, aconitase, and cis-aconitase decarboxylase, 5.7 g/L of itaconic acid was produced, which is 3.8-fold higher than that obtained with the strain without scaffold. The optimum pH and temperature for itaconic acid production were 8.5 and 30°C, respectively. When the competing metabolic network was inactivated by knock-out mutation, the itaconic acid concentration further increased, to 6.57 g/L. 相似文献
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Enhanced production of itaconic acid from corn starch and market refuse fruits by genetically manipulated Aspergillus terreus SKR10 总被引:1,自引:0,他引:1
A potent itaconic acid producing strain, Aspergillus terreus SKR10, was isolated from horticulture waste. Market refuse, apple and banana, were explored as novel substrates for itaconic acid production with yields of 20+/-2.0 and 20.0+/-1.0 g l(-1), respectively. Itaconic acid yields of 28.5+/-2.2 and 31.0+/-1.7 g l(-1) were obtained with acid and alpha-amylase hydrolyzed corn starch. The efficiency of itaconic acid production by this wild type strain was improved by ultraviolet, chemical and mixed mutagenic treatments. Two high itaconic acid yielding mutants, N45 and UNCS1 were obtained by gradient plating. These two mutants were capable of producing twice the yield of itaconic acid as the parent strain. 相似文献
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Itaconic acid is a promising organic acid and is commercially produced by submerged fermentation of Aspergillus terreus. The cultivation process of the sensitive filamentous fungus has been studied intensively since 1932, with respect to fermentation media components, oxygen supply, shearing rate, pH value, or culture method. Whereas increased final titers were achieved over the years, the productivity has so far remained quite low. In this study, the impact of the pH on the itaconic acid production was investigated in detail. The pH during the growth and production phase had a significant influence on the final itaconic acid concentration and pellet diameter. The highest itaconic acid concentration of 160 g/L was achieved at a 1.5-L scale within 6.7 days by raising and controlling the pH value to pH 3.4 in the production phase. An ammonia solution and an increased phosphate concentration were used with an itaconic acid yield of 0.46 (w/w) and an overall productivity of 0.99 g/L/h in a fed-batch mode. A cultivation with a lower phosphate concentration resulted in an equal final concentration with an increased yield of 0.58 (w/w) after 11.8 days and an overall productivity of 0.57 g/L/h. This optimized process was successfully transferred from a 1.5-L scale to a 15-L scale. After 9.7 days, comparable pellet morphology and a final concentration of 150 g/L itaconic acid was reached. This paper provides a process strategy to yield a final titer of itaconic acid from a wild-type strain of A. terreus which is in the same range as the well-known citric acid production. 相似文献
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Ramakrishnan Gnanasekaran Kannappan Panchamoorthy Gopinath Jeyaraj Iyyappan 《Preparative biochemistry & biotechnology》2013,43(7):605-609
AbstractFilamentous fungi from the genus Aspergillus are of high importance for the production of organic acids. Itaconic acid (IA) is considered as an important component for the production of synthetic fibers, resin, plastics, rubber, paints, coatings, adhesives, thickeners and binders. Aspergillus niveus MG183809 was isolated from the soil sample (wastewater unit) which was collected from Avadi, Chennai, India. In the present study, itaconic acid was successfully produced by isolated A. niveus by submerged batch fermentation. In the fermentation process, various low-cost substrates like corn starch, wheat flour and sweet potato were used for itaconic acid production. Further, the factor influencing parameters such as substrate concentration and incubation period were optimized. Maximum yield of itaconic acid (15.65?±?1.75?g/L) was achieved by using A. niveus from corn starch at a concentration of 120?g/L after 168?hr (pH 3.0). And also extraction of itaconic acid from the fermentation was performed with 91.96?±?1.57 degree of extraction. 相似文献
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Itaconic acid is a high potential platform chemical which is currently industrially produced by Aspergillus terreus. Heterologous production of itaconic acid with Escherichia coli could help to overcome limitations of A. terreus regarding slow growth and high sensitivity to oxygen supply. However, the performance achieved so far with E. coli strains is still low.We introduced a plasmid (pCadCS) carrying genes for itaconic acid production into E. coli and applied a model-based approach to construct a high yield production strain. Based on the concept of minimal cut sets, we identified intervention strategies that guarantee high itaconic acid yield while still allowing growth. One cut set was selected and the corresponding genes were iteratively knocked-out. As a conceptual novelty, we pursued an adaptive approach allowing changes in the model and initially calculated intervention strategy if a genetic modification induces changes in byproduct formation. Using this approach, we iteratively implemented five interventions leading to high yield itaconic acid production in minimal medium with glucose as substrate supplemented with small amounts of glutamic acid. The derived E. coli strain (ita23: MG1655 ∆aceA ∆sucCD ∆pykA ∆pykF ∆pta ∆Picd::cam_BBa_J23115 pCadCS) synthesized 2.27 g/l itaconic acid with an excellent yield of 0.77 mol/(mol glucose). In a fed-batch cultivation, this strain produced 32 g/l itaconic acid with an overall yield of 0.68 mol/(mol glucose) and a peak productivity of 0.45 g/l/h. These values are by far the highest that have ever been achieved for heterologous itaconic acid production and indicate that realistic applications come into reach. 相似文献