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1.
新组合菌系氧化葡萄糖酸杆菌SCB329-苏芸金芽孢杆菌SCB933能在较长时间内保持高的转化活力且具有极强的抗杂菌污染的特性。在一次投糖分批发酵的基础上,探索在控制溶氧、pH、温度等条件下,分批加入L-山梨糖发酵生产2-酮基-L-古龙酸新工艺。采用新工艺,既充分利用了菌系的优良特性,又避免了高糖浓度可能对菌系造成的不良影响。L-山梨糖最终浓度达到14%(w/v),产酸120—135g/l,转化率90%左右,发酵周期40—65h。  相似文献   

2.
一株芽孢杆菌在维生素C二步发酵中对小菌的促进作用   总被引:1,自引:0,他引:1  
从土壤中分离到1株能更好促使小菌生长和产酸的芽孢杆菌B601,作为伴生菌与巨大芽孢杆菌相比,在生长过程中,发酵液中B601活菌数小于巨大芽孢杆菌,而其芽孢数则多于巨大芽孢杆菌。对B601组成菌系的发酵条件进行优化,得到如下结果:100g/L L-山梨糖、6g/L尿素、10g/L玉米浆、培养温度30℃和发酵周期44h。与巨大芽孢杆菌组成菌系相比其底物,L-山梨糖质量浓度提高了25%,尿素下降了50%.玉米浆质量浓度下降了33%,温度提高了2℃,发酵周期缩短了4h。结果表明:B601作为伴生菌,与巨大芽孢杆菌相比,该菌株明显提高了发酵效率。  相似文献   

3.
目的:通过太空育种的方法选育获得高活性的生黑醋酸杆菌,实现维生素C的高效发酵.方法:采用太空育种的方法,对VC一步发酵菌生黑醋酸杆菌进行神州七号搭载诱变.结果:经过多轮试管初筛、摇瓶复筛,获得1株高效菌,编号为G454.23%醇浓摇瓶发酵,发酵周期缩短约2h;在适度提高通风下,可完成高醇浓度(33%)发酵,发酵周期约24h.该菌经发酵条件优化,连续5批常规生产.结果:新菌株G454的发酵稳定性好,周期均在20h以内,平均周期18.4h;与对照相比,发酵周期缩短2h,山梨糖产率12.34mg/ml/h,较对照提高7.68%.结论:筛选所得菌株454可缩短发酵周期10%.,提高山梨糖产率7.68%.  相似文献   

4.
特基拉芽胞杆菌(Bacillus tequilensis)B05是1株能显著提高小麦、玉米耐盐、耐旱能力的根际优良菌株,为提高其扩繁效率及使用效果,降低使用成本,以发酵液活菌数为指标,采用单因子预筛选和正交试验方法对菌株发酵培养基及发酵条件进行优化,在10 L发酵罐水平上进行扩大培养。结果表明,菌株B05最适发酵培养基(质量与体积分数)为麦芽浸粉1%、酵母浸粉2%、胰蛋白胨2%、复合无机盐0.3%(质量比为KH_2PO_4:K_2HPO_4:MnSO_4·H_2O=1:1:1)。最佳发酵培养条件为培养温度30℃、初始pH 6.5、摇床转速200 r/min、接种量7%、装液量40%,培养18 h菌液活菌数可达9.3×10~(10) cfu/mL,较优化前活菌数量提高了两个数量级。在含盐0.4%的盐碱土壤上进行了小麦盆栽试验,较空白对照植株生物量提高45.8%。  相似文献   

5.
在由氧化葡萄糖酸杆菌和普通生酮古龙酸杆菌构建的维生素C两菌一步发酵体系中,为了强化氧化葡萄糖酸杆菌对普通生酮古龙酸杆菌生长和产酸的促进作用,文中在氧化葡萄糖酸杆菌中构建硫辛酸合成功能模块。由含硫辛酸功能模块的氧化葡萄糖酸杆菌和普通生酮古龙酸杆菌组成的两菌一步体系,能减轻普通生酮古龙酸杆菌单菌培养时的生长抑制,强化两菌的互作关系,使维生素C前体(2-酮基-L-古龙酸,2-KGA)的产量提高到73.34 g/L(对照组为59.09 g/L),醇酸转化率提高到86.0%。研究结果为进一步优化维生素C两菌一步发酵体系提供了新思路。  相似文献   

6.
地衣芽孢杆菌2709由于易于培养、GRAS状态和完善的蛋白质分泌能力,是已经投入工业生产碱性蛋白酶的菌株。为改善该菌株的发酵生产性能,提高菌体对培养基成分的利用和碱性蛋白酶产量,对菌株的胞外分泌酶系进行完善。利用同源重组机制,在基因组复制起始位点附近引入了来源于短小芽孢杆菌的木聚糖酶基因xynA和在复制起始位点中心对称的位置引入耶氏解脂酵母来源的脂肪酶基因lipY2。整合菌株在摇瓶发酵44h时,木聚糖酶、脂肪酶酶活力分别达(58±2.07)U/mL和(207±10.62)U/mL,其分泌表达促进了地衣芽孢杆菌对发酵培养基的分解与利用,提高了培养基中还原糖、上清总氮的含量和沉淀中含氮化合物的分解;细菌生物量较地衣芽孢杆菌原始菌株提高了11.76%,同时碱性蛋白酶的发酵周期较原始菌提前了4h,碱性蛋白酶产量提高了14.41%。地衣芽孢杆菌2709分泌酶系的丰富和发酵性能的改善为在饲料行业中作为微生物制剂的地衣芽孢杆菌提供了改造的方法。  相似文献   

7.
【目的】提高谷氨酸棒状杆菌(Corynebacterium glutamicum)ATCC13032厌氧条件下的丁二酸产量,并降低发酵产物中副产物的含量。【方法】以谷氨酸棒状杆菌(Corynebacterium glutamicum)ATCC13032为出发菌,首先敲除乳酸形成的关键酶乳酸脱氢酶基因(ldh),构建ldh缺失株谷氨酸棒状杆菌ATCC13032Δldh;然后以缺失株谷氨酸棒状杆菌ATCC13032Δldh为出发菌,敲除该菌的丙酮酸脱氢酶系的E1p酶基因(aceE),构建一株双缺失突变菌株谷氨酸棒状杆菌ATCC13032ΔldhΔaceE。【结果】与供试菌比较,谷氨酸棒状杆菌ATCC13032Δldh的丁二酸产量和转化率分别提高了94.9%和32%,并且主要的副产物乳酸产量由出发菌产量的63.5 g/L降低到很微量的程度。丙酮酸脱氢酶的失活并不能完全消除副产物乙酸的形成,但乙酸的产量较ATCC13032Δldh降低了37.9%,丁二酸的产量略有提高。【结论】该重组菌具有较强的丁二酸生产工业化潜力,并且该研究方法为微生物代谢育种提供参考。  相似文献   

8.
巨大芽孢杆菌BM279是经低能N 离子注入诱变原始菌株BM80而得到的维生素C高转化率伴生菌株。通过对离子注入前后出发菌和突变株的生理、生化等生物学特点比较,探讨了离子注入巨大芽孢杆菌对2-酮基-L-古龙酸(2KGA)高转化率的促进机理。离子注入对巨大芽孢杆菌自身的生长无明显影响,BM279呈现出与BM80基本一致的生长曲线;但BM279对混菌发酵体系中产酸菌GO29的细胞增殖有显著促进作用。BM279在混菌发酵过程中分泌较多的碱性物,有利于维持GO29生长、代谢的pH环境。BM279培养42 h,其胞外活性物质对GO29的糖酸转化活力较BM80有显著提高,且分泌时间较BM80推迟6 h。利用层析技术分别从BM80、BM279胞外液中纯化了L-山梨糖脱氢酶(L-sorbose dehydrogenase,SDH)激活蛋白(SSPBM80和SSPBM279),后者比活较前者高出50%,对GO29中的SDH酶活有更强促进作用。  相似文献   

9.
目的提高罗伊乳杆菌的发酵活菌数,以提高发酵产率,降低生产成本。方法采用光电比浊法与活菌计数法,通过单因素试验和正交设计方法对罗伊乳杆菌的增殖培养基的碳源和氮源进行优化,并且绘制优化前后的生长曲线。结果罗伊乳杆菌增殖培养基中最佳的碳源、氮源种类与浓度为葡萄糖2.1%、蔗糖3.0%、牛肉膏1.5%、酵母粉1.4%,最佳的培养时间为10h。结论通过优化罗伊乳杆菌的增殖培养基,提高了发酵产率,降低了生产成本。  相似文献   

10.
研究了Vc二步混合菌发酵中氧化葡萄糖酸杆菌与巨大芽孢杆菌的生长和相互作用.结果表明,2株混合菌在发酵中可形成一种协同共生,促进2酮基L古龙酸产生;二菌协同共生的过程及条件不同,促进产酸能力亦不同.环境因子影响二菌协同共生.优化环境因子可显著改善二菌协同共生效率,并提高醇酸发酵转化率.  相似文献   

11.
在分析了新组合菌系SCB329-SCB933发酵过程特征的基础上,对流加发酵工艺中的种子培养、pH、溶氧的控制,以及发酵液初始培养基中的L-山梨糖浓度和流加起始点进行了优化,获得了比分批发酵更为满意的结果:发酵最终总糖达13%(w/v)左右,发酵周期40~50h,产2-酮基-L-古龙酸达115-130mg/ml,克分子转化率达88mol%左右。  相似文献   

12.
Microbial oxidation of D-sorbitol tol-sorbose byAcetobacter suboxydans is of commercial importance since it is the only biochemical process in vitamin C synthesis. The main bottleneck in the batch oxidation of sorbitol to sorbose is that the process is severely inhibited by sorbitol. Suitable fed-batch fermentation designs can eliminate the inherent substrate inhibition and improve sorbose productivity. Fed-batch sorbose fermentations were conducted by using two nutrient feeding strategies. For fed-batch fermentation with pulse feeding highly concentrated sorbitol (600 g/L) along with other nutrients were fed intermittently in four pulses of 0.5 liter in response to the increased DO signal. The fed-batch fermentation was over in 24 h with a sorbose productivity of 13.40 g/L/h and a final sorbose concentration of 320.48 g/L. On the other hand, in fed-batch fermentation with multiple feeds, two pulse feeds of 0.5 liter nutrient medium containing 600 g/L sorbitol was followed by the addition of 1.5 liter nutrient medium containing 600 g/L sorbitol at a constant feed rate of 0.36 L/h till the full working capacity of the reactor. The fermentation was completed in 24 h with an enhanced sorbose productivity of 15.09 g/L/h and a sorbose concentration of 332.60 g/L. The sorbose concentration and productivity obtained by multiple feeding of nutrients was found to be higher than that obtained by pulse feeding and was therefore a better strategy for fed-batch sorbose fermentation.  相似文献   

13.
Sorbose, an intermediate of Vitamin-C is produced by biological oxidation of sorbitol by Acetobacter suboxydans. The utility of oxygen vector (N-hexadecane) in enhancing the sorbose accumulation and its productivity was examined for sorbitol to sorbose bioconversion process. Shake flask fermentations were conducted using 1% to 6% (v/v) N-hexadecane. Higher sorbose production was observed in shake flask containing 1-4% N-hexadecane as compared to shake flasks without N-hexadecane. A maximum of 82.12 kgm(-)(3) sorbose accumulated in 24 h by the addition of 4% N-hexadecane as against 64.83 kgm(-)(3) sorbose without the addition of N-hexadecane. However, the concentration of sorbose produced in the same time decreased when 5% and 6% N-hexadecane were used. Batch sorbose fermentation conducted using 4% N-hexadecane demonstrated decrease in the process time from 14 h to 12 h. The productivity increased from 14.3 kgm(-)(3) h(-)(1) to 16.7 kgm(-)(3) h(-)(1) when 4% N-hexadecane was used. Fed-batch fermentation using 4% N-hexadecane was over in 20 h with a productivity of 15.9 kgm(-)(3) h(-)(1), and a sorbose accumulation of 311.68 kgm(-)(3) was obtained. The same fed-batch fermentation finished in 25 h when no N-hexadecane was used. A productivity of 12.6 kgm(-)(3) h(-)(1) and a final sorbose accumulation of 316 kgm(-)(3) were obtained. The increase in productivity and lower process time were achieved by the addition of N-hexadecane to the fermentation medium.  相似文献   

14.
目的:调节生黑醋酸杆菌生物和代谢特性,以提高发酵效率。方法:通过改变种液特性,采用半连续培养的方式,对生黑醋酸杆菌在高醇浓度下的生长特性进行了研究。结果:通过优化可以提高VC一步发酵底物山梨醇浓度达38%,32h左右发酵率达95%,山梨糖产量达360mg/ml,半连续培养连续5批之间产糖稳定,没有明显差别。结论:通过优化,有效地提高了山梨糖的产率。  相似文献   

15.
通过分枝杆菌(Mycobacteriumsp.)M3限制性降解胆固醇侧链获得了产物雄甾-4-烯-3,17-二酮(AD)和雄甾-1,4-二烯-3,17-二酮(ADD)。优化了胆固醇的投料时间、投料方式、培养基初始pH和葡萄糖浓度等工艺参数。将羟丙基-β-环糊精(HP-β-CD)应用于转化反应中,确定了HP-β-CD的最佳添加时间和添加量,使AD(D)生成率由初始对照的30%提高到60%,转化至72 h时AD(D)生成率达48%,是同期对照的4.0倍,生成率与生成速率均得到显著提高。在添加HP-β-CD的最佳转化条件下,AD(D)生成率达到70%,是初始对照的2.3倍。  相似文献   

16.
We succeeded in obtaining a strain adapted to higher temperature from a thermotolerant strain, Gluconobacter frateurii CHM43, for sorbose fermentation. The adapted strain showed higher growth and L: -sorbose production than original CHM43 strain at higher temperature around 38.5-40?°C. It was also shown to be useful even with the fermentation without temperature control. To understand the sorbose fermentation ability of the adapted strain at higher temperature, D: -sorbitol-oxidizing respiratory chain was compared with the CHM43 strain and the adapted strain. We found that the activity of pyrroloquinoline quinone (PQQ)-dependent glycerol dehydrogenase (GLDH), which is a primary dehydrogenase of the respiratory chain and responsible for L: -sorbose production, was decreased when the temperature increased, but the decreased activity of GLDH was recovered by the addition of PQQ. Since the adapted strain was found to produce more PQQ than the CHM43 strain, it was suggested that the adapted strain keeps GLDH as holoenzyme with the increased PQQ production, and thus produces more L: -sorbose and grows better under higher temperature.  相似文献   

17.
对选出的巨大芽孢杆菌突变株Bn,B5进行了生物学特性及发酵条件的研究,发现它们具耐低pH和抗高浓2KGA特性.可促进氧化葡萄糖酸杆菌生长,使其延迟期缩短,产酸增加.适宜的通气量下,摇瓶糖酸转化率提高10%~14%;当发酵pH为6.2~6.6时,转化率提高20%~30%.  相似文献   

18.
Microbial oxidation of D-sorbitol to L-sorbose is commercially important since it is the only biochemical process in Vitamin-C manufacture. The main bottleneck in the batch oxidation of D-sorbitol is that the process is severely inhibited by sorbitol. By conducting fed-batch fermentation, the inherent substrate inhibition present in batch fermentation can be eliminated. Batch fermentation with an initial sorbitol concentration of 200 g lу featured a productivity of 14.2 g lу hу and a final sorbose concentration of 200 g lу. Fed-batch fermentation conducted by feeding nutrients containing 600 g lу of sorbitol at a constant feed rate of 0.36 l hу yielded a productivity of 17.7 g lу hу and a final sorbose concentration of 320 g lу.  相似文献   

19.
The kinetics of continuous l-sorbose fermentation using Acetobacter suboxydans with and without cell recycle (100%) were investigated at dilution rates (D) of 0.05, 0.10, 0.15 and 0.3 h–1. The biomass and sorbose concentrations for continuous fermentation without recycle increased as the dilution rate was increased from 0.05 to 0.10 h–1. A maximum biomass concentration of 8.44 g l–1 and sorbose concentration of 176.90 g l–1 were obtained at D=0.10 h–1. The specific rate of sorbose production and volumetric sorbose productivity at this dilution rate were 2.09 g g–1 h–1 and 17.69 g l–1 h–1. However, on further increasing the dilution rate to 0.3 h–1, both biomass and sorbose concentrations decreased to 2.93 and 73.20 g l–1 respectively, mainly due to washout of the reactor contents. However, the specific rate of sorbose formation and volumetric sorbose productivity at this dilution rate increased to 7.49 g g–1 h–1 and 21.96 g l–1 h–1 respectively. Continuous fermentation with 100% cell recycle served to further enhance the concentration of biomass and sorbose to 28.27 and 184.32 g l–1 respectively (in the reactor at a dilution rate of 0.05 h–1). Even though, there was a decline in the biomass and sorbose concentrations to 6.8 and 83.40 g l–1 at a dilution rate of 0.3 h–1, the specific rates of sorbose formation and volumetric sorbose productivity increased to 3.67 g g–1h–1 and 25.02 g l–1 h–1.  相似文献   

20.
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