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近年来微生物腈水解酶水解腈类化合物制备有机酸已逐步受到关注。本研究分离到一株表现出较高腈水解酶活力的细菌菌株,通过形态学、生理生化实验以及16S rRNA基因序列分析将其鉴定为恶臭假单胞菌Pseudomonas putida CGMCC3830。结合单因素及响应面法对该菌株产腈水解酶的发酵条件进行了优化,获得最适培养条件为:甘油13.54 g/L,胰蛋白胨11.59 g/L,酵母粉5.21 g/L,KH2PO4 1 g/L,NaCl 1 g/L,脲1 g/L,初始pH 6.0及培养温度30℃。通过优化,酶活由2.02 U/mL提升至36.12 U/mL。对该菌株底物特异性的考察结果表明,恶臭假单胞菌腈水解酶对芳香族腈类化合物具有较高的水解活力。将其应用于烟酸的生物合成中,2 mg/mL游离细胞能90 min内将20.8 g/L 3-氰基吡啶彻底转化,制备得到相应烟酸。这些结果表明恶臭假单胞菌P.putida CGMCC3830在烟酸的规模化生产中具有一定的应用潜力。 相似文献
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来自恶臭假单胞菌的腈水解酶具有高效催化3-氰基吡啶产烟酸的能力,对表达该酶的基因psn进行发酵和产酶条件优化,通过对C源、N源、磷酸盐、金属离子、温度、诱导剂浓度和诱导时间进行单因素考察,获得最适培养基条件(g/L):葡萄糖5、蛋白胨15、酵母粉5、(NH4)2SO45、K2HPO424.5、KH2PO45.76、MgSO40.48;最佳诱导条件:培养2.5 h后添加IPTG诱导,浓度0.2 mmol/L,诱导温度30℃。在该条件下培养,重组大肠杆菌的腈水解酶比酶活可达到45.67 U/mL,比优化前提高了2.26倍。在此基础上,于5 L发酵罐上进行C、N源的补料研究,获得最适分批补料策略,发现其腈水解酶活力可达到75.40 U/mL,是优化前的3.74倍。 相似文献
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绿僵菌Ma83几丁质酶的发酵研究 总被引:1,自引:0,他引:1
本实验从虫生真菌中筛选出金龟子绿僵菌M a83菌株,它的几丁质酶合成能力最强。其产酶的适宜条件是,碳源为胶体几丁质加葡萄糖,氮源为NaNO3,培养温度为28℃,培养基起始pH 6.0;接种量为5 mL液态种,最适装液量为5 mL,添加维生素C可以提高酶活;正交实验表明培养因子的最佳组合是:NaNO31 g/L,胶体几丁质0.6 g/L,酵母膏0.05 g/L,葡萄糖0.10 g/L。根据液态培养产酶过程结果可知,当M a83菌培养6天时,几丁质酶活力达到8.1 U/mL。 相似文献
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对喇叭石蕊共生菌、藻液体培养条件进行了研究。结果表明:共生菌生长在以40g/L肌醇为碳源、2g/LL-谷氨酰胺为氮源、起始pH值为7.0的LB液体培养基中,培养温度为20℃时表现最佳。其共生藻的生长在以160g/L葡萄糖为碳源、1.75g/LNaNO3为氮源、起始pH值为5.0的BBM液体培养基中,培养温度为20℃时表现最佳。 相似文献
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《生物技术通报》2017,(7)
为实现Sulfolobus acidocaldarius ATCC 33909来源的麦芽寡糖基海藻糖合成酶(MTSase)基因tre Y在枯草芽孢杆菌(Bacillus subtilis)中的重组表达,以质粒p ET-24a(+)-tre Y为模板PCR扩增得到目的基因,并与表达载体pHY300PLK连接,转入表达宿主Bacillus subtilis CCTCC M 2016536中,重组菌在TB培养基中培养48 h后MTSase酶活达到17.5 U/m L;在此基础上对重组菌发酵条件进行优化,通过单因素实验(氮源种类、氮源复配、氮源浓度、碳源种类、葡萄糖浓度、初始pH、诱导温度)和正交实验(氮源浓度、葡萄糖浓度、初始pH、诱导温度)确定其摇瓶发酵产酶的最适培养基和培养条件为:氮源(工业蛋白胨∶棉籽粉=3∶1)48.0 g/L、葡萄糖为10.0 g/L、培养基初始pH为7.0,最适培养温度为30℃;在此条件下,MTSase的酶活可达41.5 U/m L,是优化前的2.4倍。 相似文献
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【背景】供试菌株分别是分离自山西省宁武县管涔山的肉色香蘑Lepista irina、斑褶香蘑L. panaeolus和山西省蒲县五鹿山的紫丁香蘑L. nuda 3种野生食用菌的子实体。【目的】获得3种野生食用菌的最佳培养条件。【方法】以菌丝生长速度为指标研究不同碳源、氮源、碳氮比、pH和培养温度等各因素对菌丝生长的影响,根据Box-Benhnken中心组合试验设计原理,采用3因素3水平的响应面法确定使菌丝体达到最快生长速度的最佳培养碳源、氮源和pH。【结果】肉色香蘑在葡萄糖20.9 g/L、土豆196.47 g/L、pH 6.0、培养温度21 °C的条件下,菌丝日均生长速度达到最大,为1.13 mm/d;斑褶香蘑在甘露醇17.4 g/L、酵母膏8.1 g/L、B族维生素0.1 g/L、K2HPO4 2.5 g/L、MgSO4 2.5 g/L、pH 7.9、培养温度25 °C的条件下,菌丝日均生长速度达到最大,为0.73 mm/d;紫丁香蘑在土豆200 g/L、可溶性淀粉20.5 g/L、KNO3 2.1 g/L、K2HPO4 2.5 g/L、MgSO4 2.5 g/L、B族维生素0.1 g/L、pH 7.0、培养温度25 °C的条件下,菌丝日均生长速度达到最大,为2.38 mm/d。【结论】获得了3种香蘑属菌株的最佳培养条件,为后续优质野生食用菌的引种驯化积累了相关数据和资源。 相似文献
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Yu-Cai He You-Yan Liu Cui-Luan Ma Jian-He Xu 《Biotechnology and Bioprocess Engineering》2011,16(5):901-907
We successfully modified a ferric hydroxamate spectrophotometry method for assaying glycolic acid. Comparable to the high-performance liquid chromatography (HPLC)-based method, ferric hydroxamate spectrophotometry can be used to accurately monitor the time course of glycolonitrile bioconversion. Glycolic acid was assayed simply and rapidly at room temperature (25 ~ 35°C). Optimum culture conditions were obtained using this method to assay the glycolonitrile-hydrolyzing activity of Rhodococcus sp. CCZU10-1. The preferred carbon and nitrogen sources and ideal inducer were glucose (10 g/L), a composite of peptone (10 g/L) plus yeast extract (5 g/L), and ?-caprolactam (2 mmol/L), respectively. The optimal growth temperature and initial medium pH for Rhodococcus sp. CCZU10-1 glycolonitrile-hydrolyzing activity were 30°C and pH 7.0. Modified ferric hydroxamate spectrophotometry could potentially be employed to assay other carboxylic acids. 相似文献
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Jung Kon Kim Le Nhat Young Nam Chun Si Wouk Kim 《Biotechnology and Bioprocess Engineering》2008,13(4):499-504
The optimum conditions for biological hydrogen production from food waste by Clostridium beijerinckii KCTC 1875 were investigated. The optimum initial pH and fermentation temperature were 7.0 and 40°C, respectively. When the
pH of fermentation was controlled to 5.5, a maximum amount of hydrogen could be obtained. Under these conditions, about 2,737
mL of hydrogen was produced from 50 g COD/L of food waste for 24 h, and the hydrogen content in the biogas was 38%. Hydrogen
production rate and yield were about 108 mL/L·h and 128 mL/g CODdegraded, respectively. High concentrations of acetic (< 5,000 mg/L) or butyric acid (< 3,000 mg/L) significantly inhibited hydrogen
production. 相似文献
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Youwei Zhang Tingting Li Yingbin Shen Li Wang Hui Zhang Haifeng Qian Xiguang Qi 《Biotechnology progress》2020,36(4):e2992
Alligator weed (Alternanthera philoxeroides) is a stoloniferous, amphibious and perennial herb which has invaded many parts of the world and led to serious environmental and ecological problems. In order to exploit cheap carbon source for poly(3-hydroxybutyrate) (PHB) production, alligator weed hydrolysates were prepared by acid and enzyme treatment and used for PHB production via Cupriavidus necator. The bacterium utilized alligator weed enzymatic hydrolysate and produced the PHB concentration of 3.8 ± 0.2 g/L at the conditions of pH 7.0, 27.5°C, 1.5 g/L of nitrogen source, and 25 g/L of carbon source, this exceeded the value of 2.1 ± 0.1 g/L from acid hydrolysate media at the same conditions. In order to obtain the optimum conditions of PHB production, response surface methodology was employed which improved PHB content. The optimum conditions for PHB production are as follows: carbon source, 34 g/L; nitrogen source, 2 g/L; pH, 7; temperature, 28°C. After 72 hr of incubation, the bacterium produced 8.5 g/L of dry cell weight and 4.8 g/L of PHB. The PHB was subjected to Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and Molecular weight analysis and found the melting temperature, number average molecular mass, and polydispersity were 168.20°C, 185 kDa, and 2.1, respectively. 相似文献
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E. Sánchez R. Borja P. Weiland L. Travieso A. Martín 《Bioprocess and biosystems engineering》2000,22(3):247-252
A study of the effect of temperature and pH on the kinetics of methane production and organic nitrogen and phosphorus degradation in the anaerobic digestion process of cattle manure was carried out. Two laboratory-scale batch completely mixed reactors, operating at 35v°C (mesophilic temperature), and other two, operating at 60v°C (thermophilic temperature) were used. For each temperature selected, the influent pH values were 7.6 (initial pH of the waste used) and 7.0. The apparent kinetic constants of the biomethanization process increased 2.3 times when the initial pH of the influent was increased from 7.0 to 7.6 at mesophilic temperature. The values found at thermophilic temperature were similar. The kinetic constants of methane production decreased 2.6 and 7.2 times when the operating temperature increased from 35 °C to 60v°C for the experiments carried out at initial pH of 7.0 and 7.6, respectively. The methane yield coefficient (l CH4 STP/g VS removed) also decreased when the temperature increased from 35v°C to 60v°C for the two initial pH values studied. This behaviour agreed with the major inhibition level observed at thermophilic temperature as a result of the higher organic nitrogen removal and ammonia nitrogen production observed at 60v°C. Specifically, the specific rate constants for organic nitrogen removal and ammonia nitrogen production increased 3.6 and 12 times when the temperature was increased from 35v°C to 60v°C for the experiments carried out at initial pH values of 7.0 and 7.6, respectively. In the same way, the values of the kinetic constant for phosphorus removal were 44% and 80% higher than those obtained at 35v°C for the two initial pH values above-mentioned, respectively. Finally, the experimental values of organic nitrogen and phosphorus concentrations were reproduced with deviations equal to or less than 10% and 15% in every case, respectively. 相似文献
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从天蓝色链霉菌Streptomyces coelicolor克隆得到海藻糖合酶基因 (ScTreS),在大肠杆菌Escherichia coli BL21(DE3) 中进行了异源表达,通过 Ni-NTA 亲和柱对表达产物进行分离纯化得到纯酶,经 SDS-PAGE 测定其分子量约为62.3 kDa。研究其酶学性质发现该酶最适温度35 ℃;最适pH 7.0,对酸性条件比较敏感。通过同源建模和序列比对分析,对该基因进行定点突变。突变酶K246A比酶活比野生酶提高了1.43倍,突变酶A165T相对提高了1.39倍,海藻糖转化率分别提高了14%和10%。利用突变体重组菌K246A进行全细胞转化优化海藻糖的合成条件并放大进行5 L罐发酵,结果表明:在麦芽糖浓度300 g/L、初始反应温度和pH分别为35 ℃和7.0的条件下,转化率最高达到71.3%,产量为213.93 g/L;当底物浓度增加到700 g/L时,海藻糖产量仍可达到465.98 g/L。 相似文献
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Yasemin Ispirli Doğaç Mürvet Çinar Mustafa Teke 《Preparative biochemistry & biotechnology》2013,43(2):144-157
The aim of this study was enhancing of stability properties of catalase enzyme by encapsulation in alginate/nanomagnetic beads. Amounts of carrier (10–100 mg) and enzyme concentrations (0.25–1.5 mg/mL) were analyzed to optimize immobilization conditions. Also, the optimum temperature (25–50°C), optimum pH (3.0–8.0), kinetic parameters, thermal stability (20–70°C), pH stability (4.0–9.0) operational stability (0–390 min), and reusability were investigated for characterization of the immobilized catalase system. The optimum pH levels of both free and immobilized catalase were 7.0. At the thermal stability studies, the magnetic catalase beads protected 90% activity, while free catalase maintained only 10% activity at 70°C. The thermal profile of magnetic catalase beads was spread over a large area. Similarly, this system indicated the improving of the pH stability. The reusability, which is especially important for industrial applications, was also determined. Thus, the activity analysis was done 50 times in succession. Catalase encapsulated magnetic alginate beads protected 83% activity after 50 cycles. 相似文献
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S.A. Furlan A.L.S. Schneider R. Merkle M.F. Carvalho‐Jonas R. Jonas 《Engineering in Life Science》2001,21(1):57-64
The pH, temperature and inoculum ratio for the production of β‐galactosidase by Kluyveromyces marxianus CDB 002 were optimized using sugar‐cane molasses (100 g/l) in a lactose‐free medium. The temperature optimum was evaluated in the range from 28–37 °C. Lactase production was initiated after substrate consumption indicating a reversible enzyme inhibition or catabolic repression. The specific enzyme activity after 45 h was between 456.3 U/g cell mass (37 °C) and 733.3 U/g (34 °C), whereas the highest volumetric activity was obtained at 30 °C: 21.8 U/ml. This is generally consistent with results from other authors that used whey as a carbon source. Ethanol as a by‐product reached its maximum concentration after 10–14 h (31.1–40.5 g/l), but was completely consumed afterwards. A pH of 5.5 without further control gave the best production rate for lactase (484.4 U/l × h). In this process, the pH was stable during cell growth at 5.5 and then went up to pH 7.2 after 45 h. At a fixed pH of 5.5 or 6.5, the production rates achieved 313.3 U/l × h and 233.3 U/ l × h, respectively. These results differed from those of other authors, who suggested a fixed pH at 7.0 using whey as a carbon source. There were no significant differences between inoculum ratios of 1% [v/v] and 10% [v/v] so that 1% is the preferable ratio as it is cheaper. Yeast extract (10 g/l) and peptone (20 g/l) were used as the vitamin and nitrogen source, respectively, for the studies of temperature and pH. These were substituted by corn steep liquor (100 g/l) for inoculum ratio experiments. Production of lactase using sugar cane molasses in a lactose‐free medium gave better enzyme productivity rates than obtained by other authors using whey. The optimum conditions for β‐galactosidase synthesis were a temperature of 30–34 °C and an inoculum ratio of 1% [v/v], an initial pH of 5.5 without any further control or a control of 5.5 during cell growth. Then the pH was raised up to 7. 相似文献
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Production of hydrogen from marine macro-algae biomass using anaerobic sewage sludge microflora 总被引:1,自引:0,他引:1
Jae-Il Park Jinwon Lee Sang Jun Sim Jae-Hwa Lee 《Biotechnology and Bioprocess Engineering》2009,14(3):307-315
Hydrogen was produced from various marine macro-algae (seaweeds) through anaerobic fermentation using an undefined bacterial
consortium. In this study, anaerobic fermentation from various marine macro-algae for Ulva lactuca, Porphyra tenera, Undaria pinnatifida, and Laminaria japonica was studied. From this analysis Laminaria japorica was determined to be the optimum substrate for hydrogen production. When L. japornica was used as the carbon source for enhanced hydrogen production, the optimum fermentation temperature, substrate concentration,
initial pH, and pretreatment condition were determined to be 35°C, 5%, 7.5, and BT120 (Ball mill and thermal treatments at
120°C for 30 min), respectively. In addition, hydrogen production was improved when the sludge was heat-treated at 65°C for
20 min. Under these conditions, about 4,164 mL of hydrogen was produced from 50 g/L of dry algae (L. japonica) for 50 h, with a hydrogen concentration around 34.4%. And the maximum hydrogen production rate and yield were found to be
70 mL/L·h and 28 mL/g dry algae, respectively. 相似文献
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抗草甘膦酵母菌ZM-1的分离鉴定及其生长降解特性 总被引:2,自引:0,他引:2
以福州市郊区的耕作土壤为研究材料, 利用草甘膦为选择压力, 通过富集、驯化培养, 分离出一株对草甘膦具有高耐受和降解作用的酵母菌菌株ZM-1, 结合生理生化特征及26S rDNA D1/D2区序列分析将其初步鉴定为胶红酵母菌(Rhodotorula mucilaginosa)。菌株ZM-1能以草甘膦为唯一碳、氮源生长, 对草甘膦的最高耐受浓度为50 g/L。在草甘膦初始浓度为1 g/L的无机盐培养基中, 30°C、150 r/min 摇床振荡培养7 d, 草甘膦降解率为85.38%。适合菌株ZM-1生长及降解草甘膦的最佳条件为: 草甘膦初始浓度1 g/L, 接种量4%, 温度30°C, pH 值5.5-6.0, 装料量50 mL/250 mL。菌株ZM-1是一株良好的草甘膦耐受菌, 可用于草甘膦污染环境的生物修复, 也可能成为转基因抗草甘膦作物的一个很好资源。 相似文献