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研究了真养产碱杆菌突变株65-7,以葡萄糖为主原料,添加丙酸或戊酸,采用二步发酵积累共聚物聚β-羟基丁酸-β-羟基戊酸(PHBV)。摇瓶总发酵时间为50h,细胞干重达7-11g/L,共聚物含量占细胞干重的70%以上,其中β-羟基戊酸(3HV0含量占PHBV的10-72%,主要取决于不同碳源的组成,丙酸和戊酸对HV的转化率分别为0.41-0.63gHV/g丙酸和0.40-0.74gHV/g戊酸,制得 相似文献
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igenes eutrophus培养过程的研究表明,氮源的限制或缺乏可刺激细胞大量积累聚-β-羟基丁酸(PHB),但PHB合成期氮源的完全缺乏,会导致细胞的PHB合成速率迅速下降;氧的限制也可刺激A.eutrophus合成PHB,但胞内PHB的积累量远小于氮源控制下的情况。在细胞的不同生长期限制氮源的供应会明显影响PHB的发酵过程,当残留菌体浓度达到20g/L至30g/L时停止流加氨水,可以得到较好的发酵水平,细胞干重,PHB含量和PHB浓度可分别达到61.9g/L、80.5%和49.0g/L。 相似文献
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一株产碱极端嗜盐杆菌 总被引:3,自引:0,他引:3
从青海省大柴旦盐湖中分离到一株极端嗜盐杆菌。该菌株在培养过程中产碱,革兰氏阴性,细胞杆状,0.7-1.0×2-3μm,极生鞭毛运动,绝对好氧,以氨基酸作唯一碳源。不利用碳水化合物,生长所需盐(NaCl)浓度在1 2%以上,最适盐浓度为l 8%。生长pH范围6-l0,最适pH9。MgSO4·7H2Oo-3%对生长无明显影响。细胞蛋白质酸性,不含二氨莲庚二酸和胞壁酸,含甘油二醚键化合物,不具有色素。根据以上特征,将该菌株定为一个新种,定名为产碱嗜盐杆菌(Halobocierium haloalcaligenum n.sp.)。 相似文献
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在摇瓶条件下,对真养产碱杆菌(Alcaligeneseutrophus)的3羟基丁酸与3羟基戊酸共聚物(PHBV)发酵过程中HV组分的前体物质———丙酸的加入时间和加入量进行了研究,结果表明,PHBV中HV组分含量与丙酸的加入时间和加入量有密切的关系,丙酸的最佳加入时间为菌体生长阶段结束后的多聚物合成初期;尽管高浓度丙酸下可获得较高的HV组分含量,但会明显抑制菌体的生长和产物的合成。通过对2L小罐中PHBV合成阶段流加不同糖/酸比混合液所得的发酵结果的比较,并在综合考虑PHBV浓度、HV组分含量、生产强度和生产成本等基础上,提出了在PHBV合成期流加液的糖/酸比应随菌体对丙酸利用能力的下降而不断增加的流加策略,在此条件下,细胞干重、PHBV浓度和PHBV含量和HV摩尔分率分别达到521g/L、408g/L、783%和162mol%,HV组分对丙酸的产率系数为05g/g,PHBV的生产强度达到074g/(L/h)。 相似文献
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在摇瓶条件下,对真养产碱杆菌(Alcaligeneseutrophus)的3羟基丁酸与3羟基戊酸共聚物(PHBV)发酵过程中HV组分的前体物质———丙酸的加入时间和加入量进行了研究,结果表明,PHBV中HV组分含量与丙酸的加入时间和加入量有密切的关系,丙酸的最佳加入时间为菌体生长阶段结束后的多聚物合成初期;尽管高浓度丙酸下可获得较高的HV组分含量,但会明显抑制菌体的生长和产物的合成。通过对2L小罐中PHBV合成阶段流加不同糖/酸比混合液所得的发酵结果的比较,并在综合考虑PHBV浓度、HV组分含量、生产强度和生产成本等基础上,提出了在PHBV合成期流加液的糖/酸比应随菌体对丙酸利用能力的下降而不断增加的流加策略,在此条件下,细胞干重、PHBV浓度和PHBV含量和HV摩尔分率分别达到521g/L、408g/L、783%和162mol%,HV组分对丙酸的产率系数为05g/g,PHBV的生产强度达到074g/(L/h)。 相似文献
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补料培养提高真养产碱杆菌产3-羟基丁酸和3-羟基戊酸共聚物生产强度的研究 总被引:1,自引:0,他引:1
对Alcaligenes eutrophus进行高密度培养,研究表明在发酵过程中进行有效控制,可以较大幅度地提高3-羟基丁酸和3-羟基戊酸共聚物[P(3HB-co-3HV)]的生产强度。实验中选择使用限氮的方法积累P(3HB-co-3HV),分别采用丙酸和戊酸为3HV前体,对摇瓶种子生长状态,停氮时机对菌体生产P(3HB-co-3HV)的影响以及补酸(3HV前体)策略进行了研究,在6.6L罐中,以葡萄糖为碳源,以丙酸为3HV前体培养50h,细胞干重,PHA产量,PHA含量分别达到149.9g/L,149.9g/L,83.3%(其中3HV组分占PHA的12.4mol%),生产强度达到2.50(g.h^-1.L^-1);以戊酸为3HV前体培养45h,细胞干重,PHA产量,PHA含量分别达到160.2g/L,119.0g/L,74.2%(其中3HV组分占PHA的17.7mol%)生产强度达到2.64(g.h^-1.L^-1)。 相似文献
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Behnam Taidi David A. Mansfield Alistair J. Anderson 《FEMS microbiology letters》1995,129(2-3):201-205
Abstract Radiolabelled glucose was added to a batch culture of Alcaligenes eutrophus during the accumulation of poly(3-hydroxybutyrate) (PHB) to label newly synthesized polymer. The specific radioactivity of the polymer continued to increase, by approximately 30%, after the cessation of PHB accumulation, indicating that turnover of PHB was occurring. Fractionation of PHB showed that high molecular mass polymer was gradually replaced by PHB of lower molecular mass. Turnover of PHB is the cause of the slow decline in the molecular mass of PHB following the cessation of polymer accumulation but is unlikely to be the sole reason for the more rapid decrease in the molecular mass of PHB during the accumulation phase. 相似文献
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The effect of nickel salt on growth of the nickel-resistant wild type strain Alcaligenes eutrophus CH34, which harbours two plasmids, and on its partially or totally cured derivatives as well as of the wild type strain H16 was studied. Plasmid pMOL28-mediated nickel resistance turned out to be an inducible property. Full resistance is induced during growth in the presence of 0.03–3.0 mM NiCl2. Induction requires growth. While plasmid-free cells accumulate nickel at a high rate, the pMOL28-harbouring-induced cells accumulate only negligibly small amounts of nickel. It is concluded that pMOL28 mediates a protective mechanism preventing the cells to accumulate nickel ions intracellularly at toxic concentrations. 相似文献
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Abstract The membrane-bound hydrogenase was localized in cells of Alcaligenes eutrophus by electron microscopic immunocytochemistry. Post-embedding labeling performed on ultrathin sections revealed that the enzyme was located predominantly (80%) at the cell periphery in autotrophically and heterotrophically grown bacteria harvested from the exponential phase of growth. In the stationary growth phase, however, only 50% of the enzyme was found at the cell periphery; the remaining 50% was distributed over the cytoplasm. The relative amount of electron microscopic label per cell as seen by application of the protein A—gold technique was higher in cells grown autotrophically as compared to cells grown heterotrophically on fructose. Derepression of the enzyme was followed electron microscopically in a substrate-shift experiment (growth on fructose, followed by a shift to glycerol). Major amounts of the enzyme appeared to undergo a reattachment to the cytoplasmic membrane under these conditions, starting with a reduced location of the enzyme in the cytoplasm and an accumulation in cell areas close to the cytoplasmic membrane. These findings indicate that the 'membrane-bound' hydrogenase (i.e., that material enriched as membrane-bound enzyme according to the appropriate activity test) is not, in fact, membrane bound or membrane integrated but membrane associated. It may or may not interact with the cytoplasmic face of the cytoplasmic membrane, depending on the growth phase and conditions. 相似文献
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Production of poly(3-hydroxybutyric acid) by fed-batch culture of Alcaligenes eutrophus with glucose concentration control 总被引:1,自引:0,他引:1
Alcaligenes eutrophus NCIMB 11599 was cultivated to produce poly(3-hydroxybutyric acid) (PHB) from glucose by the automatic fed-batch culture technique. The glucose concentration of the culture broth was controlled at 10 to 20 g/L by two methods: using exit gas data obtained from a mass spectrometer and using an on-line glucose analyzer. The effect of ammonium limitation on PHB synthesis at different culture phases was studied. The final cell concentration, PHB concentration, and PHB productivity increased as ammonia feeding was stopped at a higher cell concentration. High concentrations of PHB (121 g/L) and total cells (164 g/L) were obtained in 50 h when ammonia feeding was stopped at the cell concentration of 70 g/L. The maximum PHB content reached 76% of dry cell weight and the productivity was 2.42 g/L h with the yield of 0.3 g PHB/g glucose. 相似文献
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Abstract Electron microscopy of negatively stained samples of the membrane-bound hydrogenase isolated from Alcaligenes eutrophus was used to obtain enzyme images with an estimated resolution of 2.5 nm. The two subunits with shapes similar to the letter 'U' making up the enzyme could be seen to be joined in two planes orthogonal to each other, making contact with their concave sides. In face-on view, the particle exhibited bilateral symmetry. 相似文献
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Kinetic analysis on formation of poly(3-hydroxybutyrate) from acetic acid by Ralstonia eutropha under chemically defined conditions 总被引:1,自引:0,他引:1
Batch cultures of Ralstonia eutropha in chemically defined media with acetic acid (HAc) as the sole carbon source were conducted to investigate acetate utilization,
formation of poly(3-hydroxybutyrate) (PHB) and growth of active biomass (ABM) under different carbon to nitrogen (C/N) weight
ratios. The specific acetate utilization rate based on ABM approached 0.16 g/g ABM h−1, which was not affected very much by the extracellular HAc concentration from 1 to 5 g/l, but was affected by the C/N weight
ratio. A low C/N ratio or high nitrogen supply sped up the specific acetate utilization rate to produce more ABM and less
PHB. A high HAc concentration (>6 g/l), however, depressed acetate utilization as well as the ABM growth and PHB formation.
A high cell mass concentration enhanced the tolerance of R. eutropha to the toxicity of HAc at pH 7 to 8.5. The viscosity-average molecular size of PHB generally increased first and then declined
in batch cultures. Larger PHB molecules and less PHB per ABM were produced at a low C/N ratio with enough nutrient nitrogen
than those under a high C/N ratio with less nutrient nitrogen available. Journal of Industrial Microbiology & Biotechnology (2001) 26, 121–126.
Received 06 June 2000/ Accepted in revised form 21 October 2000 相似文献
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Christina Wallrabenstein Elisabeth Hauschild Bernhard Schink 《FEMS microbiology letters》1994,123(3):249-254
Abstract In water-in-oil microemulsion the membrane-associated F420 -hydrogenase of Methanobacterium thermoautotrophicum (strain Marburg) and the membrane-bound hydrogenase of Alcaligenes eutrophus H 16 (MBH) showed prolonged activity at elevated temperatures (measured as hydrogen production) as compared to aqueous buffer solution. The temperature optimum of the reactions was about 15°C higher than in aqueous buffer solution. Activity of the almost completely inactivated F420 -hydrogenase could be partially recovered by transfer into microemulsion. 相似文献
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Abstract The localization of the soluble NAD-dependent hydrogenase in cells of Alcaligenes eutrophus PHB− 4 was investigated using the protein A-gold technique as a post-embedding immunoelectron microscopic procedure. The enzyme was found throughout the cytoplasm of the cells. Autotrophic cells harvested in the logarithmic phase of growth exhibited a higher degree of labeling as compared to autotrophic cells from the stationary growth phase. Heterotrophic cells showed an almost identical labeling intensity in all growth phases. In a substrate-shift experiment (from fructose to glycerol, performed in the stationary growth phase), high amounts of newly synthesized enzyme could be observed two hours after the shift. This enzyme was located, as inclusion bodies, in the DNA region of the cells. 相似文献