新型杀虫剂——Spinosad发酵工艺的研究

采用₆₀Co正交设计的方法 ,选择最优种子培养基配方和发酵培养基配方 ,在此基础上进行UV、₆₀Co等诱变 ,得突变株 ,其发酵水平较原始菌株提高了 1 5 0 %。同时 ,对菌株的发酵接种量、发酵液处理及发酵曲线也作了研究。     

金针菇在淀粉废水中发酵的营养条件研究

用摇瓶试验对金针菇菌丝体在淀粉废水中培养的营养条件进行了研究。结果表明,利用淀粉废水进行金针菇液体发酵的最适营养条件为：经液化处理的淀粉废水,加KH₂PO₄0.25 g/100 mL,MgSO₄·7H₂O0.05g/100mL,V_B1150μg/L,V_B250μg/L,pH5.40。测定了该营养条件下菌体的生长曲线及发酵过程中培养基残糖的变化。发酵周期为7d,发酵终点生物量达2.08 g/100 mL,COD去除率为70.8%。     

枯草芽胞杆菌甘露聚糖酶发酵条件优化

旨在以枯草芽胞杆菌Bacillus subtilis J为生产菌株,发酵生产β-甘露聚糖酶,通过优化产酶条件,以达到提高β-甘露聚糖酶产量的目的。利用DNS比色法检测β-甘露聚糖酶活力,采用单因素试验,研究碳氮源种类及碳氮源浓度、温度、pH、接种量和装液量对菌株Bacillus subtilis J发酵产β-甘露聚糖酶的影响,结合响应面试验设计确定菌株Bacillus subtilis J发酵产甘露聚糖酶的最优发酵培养条件。单因素试验和响应面试验得到最优的发酵条件为魔芋粉28 g/L,胰蛋白胨21 g/L,K₂HPO₄ 6 g/L,MgSO₄·7H₂O 1 g/L,温度31 ℃,pH值 8.5,接种量1%（体积分数）,装液量50 mL/250 mL,发酵周期24 h。利用优化后的培养基生产β-甘露聚糖酶,其酶活力达到84.38 U/mL,是初始发酵培养基产酶活力的3.36倍。通过对发酵条件的优化,大幅度提高了β-甘露聚糖酶的产量,为其工业生产提供数据参考。     

一株新海洋粘质沙雷氏菌产灵菌红素发酵条件优化

灵菌红素是由微生物产生的一种红色次级代谢产物,因其具有抗菌、抗癌和抗疟疾等功效,受到了生物医药领域的广泛关注。微生物发酵是当前产灵菌红素的主要方法,分离筛选高产灵菌红素的微生物、优化发酵条件是提高灵菌红素产率的重要途径。本研究从深圳湾筛选出一株含有红色色素的菌株,并基于16S rRNA基因序列对该菌株进行了系统发育分析和物种鉴定。紫外可见光全波长扫描和HPLC-MS图谱分析证明,该菌株所产红色色素为灵菌红素。进一步通过单因素试验和正交优化法优化了该菌产灵菌红素的发酵条件和发酵培养基组分。系统发育分析表明,该菌株为一株海洋粘质沙雷氏菌（Serratia marcescens）,并将其命名为S. marcescens SOCE 001。产灵菌红素的最佳发酵条件为：温度28 ℃、振荡培养转速220 r/min、培养基pH 7。发酵培养基最佳组合为：果糖添加量2 g/L、蛋白胨添加量10 g/L,MgSO₄添加量2 g/L。优化发酵条件后,经24 h培养, 灵菌红素产量可达2.468 g/L。     

保水功能菌枯草芽胞杆菌LX-1固态发酵的工艺优化

γ-聚谷氨酸(γ-PGA)对土壤保水和提高植物抗逆性具有明显作用,为了利用农产品加工下脚料发酵生产含有γ-PGA的保水功能肥料,对福建省微生物研究所环境微生物研究室分离到的产γ-PGA的枯草芽胞杆菌(Bacillus subtilis)LX-1的固态发酵培养基配比进行优化。实验以发酵产物的荧光素双醋酸酯酶(FDA)酶活和增比黏度为指标,在通过单因素实验选定固态发酵料的碳源、氮源、无机盐溶液的最佳配比以及无机盐较佳添加量的基础上,通过拟水平均匀设计U₇* (7⁴试验,得出菌株LX-1固态发酵的最佳培养基配方：V豆粕V麦麸V无机盐溶液=644,其中无机盐溶液的最佳配方为K₂HPO₄·3H₂O 5.24 g/L、MgSO₄·7H₂O 0.78 g/L、NaCl 11.67 g/L。为利用农产品加工下脚料发酵生产含γ-PGA保水肥料提供参考。     

基因工程菌Pichia pastoris高密度培养条件研究*

基因工程菌pichiapastoris最佳种子培养基为添加 4mL/LPTMl的BMGY培养基 ;全合成高密度摇瓶培养基是甘油 4% ,(NH₄) ₂ SO₄1 0g/L ,CaSO₄0 .93g/L ,K₂ SO₄1 8.2g/L ,MgSO₄·7H₂O 1 4.9g/L ,0 1mol/L磷酸缓冲液 (pH =6     

无机盐和碳氮源对青霉PT95类胡萝卜素产率的影响*

供试的 4种无机盐中 ,K₂ HPO₄的单因子效应最好 ;K₂ HPO₄+KCl +MgSO₄表现出最好的正协同效应。 5种碳源都能被PT95菌株利用 ,麦芽糖和蔗糖是最适碳源。在以酵母膏为氮源的培养基上 ,PT95菌株的菌核生物量最高 ;而在以蛋白胨为氮源的培养基上 ,类胡萝卜素产率最高 ;铵盐和尿素对菌核形成不利 ;硝酸钠是最好的无机氮源。培养基中的含氮量保持在 0.24～ 0.48g L,含     

2-酮基-D-葡萄糖酸产生菌种子培养基的优选

本文报道2-酮基-D-葡萄糖酸产生菌种子培养基优选的结果。用生产菌株荧光假单胞菌K1005和球状节杆菌K1022进行试验,其较好的种子培养基为:葡萄糖2%,玉米浆1.0%,尿素0.2%,KH₂PO₄0.1-0.2%,MgSO₄·7H₂O 0.05%,pH7.0。廉价的玉米浆和尿素可以替代昂贵的牛肉膏、蛋白胨和酵母膏。所优选的种子培养基的原材料成本大幅度下降。     

深海低温脂肪酶基因工程菌LIP001发酵条件的优化

对从深海沉积物宏基因组文库中获得的产低温脂肪酶基因工程菌LIP001进行了发酵条件优化。通过单因素试验对LIP001产脂肪酶的主要影响条件进行了探讨,确定了培养条件为30℃、pH7.0、接种量5%、装液量50ml。在单因素的基础上通过正交试验优化了影响重组菌LIP001产酶主要因素:橄榄油、酵母粉、磷酸盐、MgSO₄,确定了培养基为橄榄油1%、酵母粉0.5%、蛋白胨1%、硫酸铵0.5%、磷酸盐0.5%、MgSO₄为0.2%、氯霉素12.5μg/ml,优化后的脂肪酶活为1980U/ml,比优化前提高了54.7%,为大规模发酵奠定了基础。采用5升发酵罐方法试验,酶活达到2420U/ml。     

选育抗老化啤酒酵母提高啤酒风味稳定性的研究

对一株啤酒酵母青②进行紫外线诱变 ,在蛋氨酸浓度为 15g L的耐性平板上筛选获得一株A₂₇菌株。为使A₂₇菌株的蛋氨酸耐性特征稳定遗传 ,在 11℃、稀释率为0.035h^-1 的条件下对A₂₇菌株进行高浓度蛋氨酸 (20g/L)连续驯养 ,然后分离得到一株M^I₄菌。在锥形瓶中连续发酵5代后 ,与A₂₇菌株相比 ,M^I₄ 菌株发酵液中GSH浓度高44% ,TBA值低 24% ,主酵液RSV值高 77% ,且遗传稳定性明显提高 :连续传代 5次后 ,M^I₄ 菌株胞内GSH含量基本不变 ,而A₂₇菌则下降了22%。在相同的糖化和发酵工艺条件下 ,对优选株M^I₄和出发株啤酒酵母青②进行 1m3发酵罐中试。与出发株青②相比 ,两者的总高级醇与酯量几乎不变 ,常规指标没有显著差别 ,品尝风味也基本一致。但M^I₄菌株发酵液中GSH浓度提高了 30% ,TBA值降低了19% ,成品啤酒的RSV值则提高了92% ,表明优选株M^I₄是一株具有抗老化能力的优良啤酒酵母 ,能够提高啤酒的风味稳定性.     

Production of poly-3-hydroxybutyrate by Bacillus sp. JMa5 cultivated in molasses media

A strain of Bacillus sp. coded JMa5 was isolated from molasses contaminated soil. The strain was able to grow at a temperature as high as 45°C and in 250 g/l molasses although the optimal growth temperature was 35–37°C. Cell density reached 30 g/l 8 h after inoculation in a batch culture with an initial concentration of 210 g/l molasses. Under fed-batch conditions, the cells grew to a dry weight of 70 g/l after 30 h of fermentation. The strain accumulated 25–35%, (w/w) polyhydroxybutyrate (PHB) during fermentation. PHB accumulation was a growth-associated process. Factors that normally promote PHB production include high ratios of carbon to nitrogen, and carbon to phosphorus in growth media. Low dissolved oxygen supply resulted in sporulation, which reduced PHB contents and dry weights of the cells. It seems that sporulation induced by reduced supply of nutrients is the reason that PHB content is generally low in the Bacillus strain.     

Bicarbonate is a stimulus in the inter-species induced sporulation of strict anaerobic Syntrophomonas erecta subsp. sporosyntropha

Previously Syntrophomonas species had been described as the bacteria those did not form spores, however, in our previous studies, a newly isolated S. erecta subsp. sporosyntropha JCM13344^T was found to form spores in the co-culture with methanogens, while not in mono-culture or in co-culture with sulfate reducer. In this study, we examined the sporulation stimulus conferred by methanogens in the co-culture. By reducing bicarbonate in mono-culture and sulfate-reducing co-culture, we could induce S. erecta subsp. sporosyntropha JCM13344^T to form spores, so that bicarbonate at lower concentration was determined as another stimulus for sporulation. Based on the substrate degradation by strain JCM13344^T in different concentration of bicarbonate vs at different pHs, it was suggested that bicarbonate could stimulate the sporulation by mediating a nutrient deprivation but not pH drop. To further confirm the sporulation potential of this group of bacteria, spo0A fragments were amplified from strain JCM13344^T as well as all the recognized Syntrophomonas species, confirming that they were members of the spore-forming group. Since sporulation is a kind of response of spore-forming bacteria to environmental stresses, the observation in this work implies that stresses can be created even between the mutual beneficial partners, in this case, inducing sporulation.     

Effect of the Medium Composition and Cultivation Conditions on Sporulation in Chemolithotrophic Bacteria

The possibility of regulating endospore formation by changing cultivation conditions was for the first time shown in acidophilic chemolithotrophic bacteria Sulfobacillus thermosulfidooxidans type strain 1269 and the thermotolerant strain K1 formerly described as S. thermosulfidooxidans subsp. thermotolerans. Suppression of sporulation occurred when these strains were cultured in Manning's liquid medium with yeast extract. This medium was optimized by gradually reducing the concentrations of ferrous iron salts (the source of energy), phosphorous, nitrogen, and yeast extract and simultaneously increasing the concentrations of calcium, magnesium, and manganese (the elements important for sporogenesis) to attain higher yields of endospores by strains 1269 and K1. As a result, a new medium A was proposed, in which, under aeration, the life cycle of the strains studied culminated in sporulation at a level of 45 and 60%, respectively, of the total cell number. In a series of additional tests, the growth temperature and medium pH were adjusted to obtain the maximum yield of endospores. The optimal ranges found were 40–50°C and pH 1.8–2.2 for strain 1269 and 35–40°C and pH 2.5–2.7 for strain K1. An even higher yield of endospores, amounting to 55 and 75% for strains 1269 and K1, respectively, was obtained when the above growth conditions were combined (growth on medium A at optimal temperatures and pH under static conditions). Our results suggest a new approach to optimizing sporulation by acidophilic chemolithotrophs, which consists in limiting the energy and nutrient sources and using temperature and pH values within the tolerance bounds of these cultures but outside their growth optimum ranges.     

一株维氏气单胞菌发酵培养基优化及其制备疫苗免疫效力比较

采用单因素试验、响应面试验法对维氏气单胞菌（Aeromonas veronii）发酵培养基的氮源、碳源、无机盐和磷酸盐成分及用量进行优化组合,确定优化培养基组成：胰蛋白胨10.8 g/L,葡萄糖5.0 g/L,牛肉膏3.0 g/L,磷酸二氢钾2.0 g/L,硫酸镁0.4 g/L,NaCl 5.0 g/L。并与基础培养基的发酵活菌数、制备的灭活疫苗免疫效力进行比较,经过验证试验绘制维氏气单胞菌在优化培养基条件下的7 L发酵罐生长曲线。在优化发酵培养基条件下,维氏气单胞菌活菌数为5.94×10⁹ cfu/mL,比基础培养基增幅43.13%;制备的灭活疫苗相对保护率为77.78%,比基础培养基提高了14.81%。7 L发酵罐发酵培养10 h,活菌数达到最大8.85×10⁹ cfu/mL。通过对发酵培养基的优化,可以获得低成本、优质高效的维氏气单胞菌发酵菌液,为今后维氏气单胞菌灭活疫苗规模化发酵培养提供参考。     

Citric acid wastewater as electron donor for biological sulfate reduction

Citrate-containing wastewater is used as electron donor for sulfate reduction in a biological treatment plant for the removal of sulfate. The pathway of citrate conversion coupled to sulfate reduction and the microorganisms involved were investigated. Citrate was not a direct electron donor for the sulfate-reducing bacteria. Instead, citrate was fermented to mainly acetate and formate. These fermentation products served as electron donors for the sulfate-reducing bacteria. Sulfate reduction activities of the reactor biomass with acetate and formate were sufficiently high to explain the sulfate reduction rates that are required for the process. Two citrate-fermenting bacteria were isolated. Strain R210 was closest related to Trichococcus pasteurii (99.5% ribosomal RNA (rRNA) gene sequence similarity). The closest relative of strain S101 was Veillonella montepellierensis with an rRNA gene sequence similarity of 96.7%. Both strains had a complementary substrate range.     

利用核糖体工程选育丙酮丁醇菌提高丁醇产量

利用核糖体工程技术对丙酮丁醇梭菌Clostridium acetobutylicum L7进行诱变筛选,以获得丁醇高产菌株。使用链霉素诱变C.acetobutylicum L7并结合设计的平板转接逐次提高链霉素浓度的筛选路线,获得丁醇产量较高的菌株S3。结果表明,S3丁醇产量为(12.48±0.03)g/L,乙醇产量为(1.70±0.07)g/L,相对于原始菌分别提高了11.2%及50%;丁醇/葡萄糖转化率由原始菌的0.19提高到0.22,丁醇生产率达到0.24 g/(L.h),相比提高30.5%;耐受丁醇浓度由原始菌的12 g/L提高到14 g/L;发酵液粘度下降到4 mPa/s,同比降低了60%,利于后续分离工作的进行,降低发酵成本。进一步研究工作表明,S3菌株遗传稳定性良好。因此,核糖体工程技术是一种选育丁醇高产菌株的有效方法。     

一株芽孢杆菌在维生素C二步发酵中对小菌的促进作用

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。     

Effect of the medium composition and cultivation conditions on sporulation in chemolithotrophic bacteria

The possibility of controlling endospore formation by changing cultivation conditions was for the first time shown in acidophilic chemolithotrophic bacteria Sulfobacillus thermosulfidooxidans type strain 1269 and the thermotolerant strain K1 formerly described as "S. thermosulfidooxidans subsp. thermotolerans". Suppression of sporulation occurred when these strains were cultured in Manning's liquid medium with yeast extract. This medium was optimized by gradually reducing the concentrations of ferrous iron salts (the source of energy), phosphorous, nitrogen, and yeast extract and simultaneously increasing the concentrations of calcium, magnesium, and manganese (the elements important for sporogenesis) to attain higher yields of endospores by strains 1269 and K1. As a result, a new medium A was proposed, in which the life cycle of the strains studied culminated in sporulation at a level of 45 and 60%, respectively, of the total cell number. In a series of additional tests, the growth temperature and medium pH were adjusted to obtain the maximum yield of endospores. The optimal ranges found were 40-50 degrees C and pH 1.8-2.2 for strain 1269 and 35-40 degrees C and pH 2.5-2.7 for strain K1. An even higher yield of endospores, amounting to 55 and 75% for strains 1269 and K1, respectively, was obtained when the above growth conditions were combined (growth on medium A at optimal temperatures and pH). Our results suggest a new approach to optimizing sporulation by acidophilic chemolithotrophs, which consists in limiting the energy and nutrient sources and using temperature and pH values within the tolerance bounds of these cultures but outside their growth of optimum ranges.     

Persistence and functional impact of a microbial inoculant on native microbial community structure,nutrient digestion and fermentation characteristics in a rumen model

Small sub-unit (SSU) rRNA-targeted oligonucleotide probes were used to monitor the persistence of a genetically engineered bacterium inoculated in model rumens. Eight dual flow continuous culture fermenters were operated with either standard artificial saliva buffer or buffer with chondroitin sulfate (0.5 g/l) added. After 168 h of operation, fermenters were inoculated with Bacteroides thetaiotaomicron BTX (BTX), at approximately 1% of total bacteria. B. thetaiotaomicron was quantified using a species-specific probe and shown to persist in fermenters 144 h after inoculation (relative abundance 0.48% and 1.42% of total SSU rRNA with standard and chondroitin sulfate buffers, respectively). No B. thetaiotaomicron SSU rRNA was detected in fermenter samples prior to inoculation with strain BTX. Relative abundances of Bacteria, Eucarya and Archaea were not affected by either inoculation or buffer type. Fiber digestion, in particular the hemicellulose fraction, increased after strain BTX addition. Chondroitin sulfate addition to the buffer increased bacterial nitrogen flow in fermenters, but did not alter fiber digestion. Neither inoculum nor buffer type altered total short chain fatty acid (VFA) concentrations but proportions of individual VFA differed. In model rumens, B. thetaiotaomicron BTX increased fiber digestion when added to mixed ruminal microbes, independent of chondroitin sulfate addition; but further study is needed to determine effects on other fiber-digesting bacteria.     

番茄青枯病拮抗菌筛选鉴定及其发酵条件初探

从健康番茄根系采样,筛选出4株对番茄青枯病有较强拮抗作用的菌株,在NA培养基上抑菌圈直径>9 mm。其中拮抗菌株YB6抑菌活性最强且拮抗效果稳定,通过形态学观察及部分生理生化特征测定,初步确定为节杆菌属。通过单因素试验进行了发酵条件初步研究,得到适宜的发酵条件为:发酵时间3 d,培养温度30°C,初始pH值9.0,接种量3%,转速100 r/min,碳源蔗糖,氮源酵母浸膏。通过初步优化后拮抗菌株抑菌活性明显增强,最终对青枯病菌SST-Y和G2M1.70抑菌圈直径与NB培养基相比增加了76.72%和81.14%,差异显著。