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11.
Production of polyhydroxybutyrate by the marine photosynthetic bacterium Rhodovulum sulfidophilum P5
The effects of different NaCl concentrations, nitrogen sources, carbon sources, and carbon to nitrogen molar ratios on biomass accumulation and polyhydroxybutyrate (PHB) production were studied in batch cultures of the marine photosynthetic bacterium Rhodovulum sulfidophilum P5 under aerobic-dark conditions. The results show that the accumulation of PHB in strain P5 is a growth-associated process. Strain P5 had maximum biomass and PHB accumulation at 2%-3% NaCl, suggesting that the bacterium can maintain growth and potentially produce PHB at natural seawater salinity. In the nitrogen source test, the maximum biomass accumulation (8.10±0.09 g/L) and PHB production (1.11±0.13 g/L and 14.62%±2.25% of the cell dry weight) were observed when peptone and ammonium chloride were used as the sole nitrogen source. NH 4 + -N was better for PHB production than other nitrogen sources. In the carbon source test, the maximum biomass concentration (7.65±0.05 g/L) was obtained with malic acid as the sole carbon source, whereas the maximum yield of PHB (5.03±0.18 g/L and 66.93%±1.69% of the cell dry weight) was obtained with sodium pyruvate as the sole carbon source. In the carbon to nitrogen ratios test, sodium pyruvate and ammonium chloride were selected as the carbon and nitrogen sources, respectively. The best carbon to nitrogen molar ratio for biomass accumulation (8.77±0.58 g/L) and PHB production (6.07±0.25 g/L and 69.25%±2.05% of the cell dry weight) was 25. The results provide valuable data on the production of PHB by R. sulfidophilum P5 and further studies are on-going for best cell growth and PHB yield. 相似文献
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青岛海域大面积聚集漂浮浒苔的显微观测 总被引:4,自引:1,他引:3
对近期在青岛海域大面积聚集漂浮的浒苔(Enteromorpha prolifera (Muell)J.Ag)进行常规显微镜观察,发现细胞内存在大小约1μm的可动的颗粒状结构。分别采用鞭毛染色和扫描电镜观察的方法对其进行了初步研究,均未发现此颗粒状可动结构具有鞭毛。用透射电镜对浒苔细胞的超微结构特征进行了观察,显示浒苔细胞壁致密而厚,每个浒苔细胞有1个片状叶绿体,贴近于细胞壁分布,淀粉粒含量丰富,但依然未发现胞内颗粒状结构具有鞭毛。 相似文献
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用单因素分析法研究在培养基中缺乏铁、镁、微量元素液、维生素液时对阴沟肠杆菌 XA-2生长的影响。实验发现,铁和镁对该菌的生长影响显著,而缺乏微量元素液、维生素液对该菌的生长影响不明显。缺铁培养时该菌在稳定期的菌浊浓度 OD600nm为1.2586,缺镁培养时菌浊浓度为0.6988,仅为完全培养时菌浊浓度的三分之一,其中,镁对该菌生长的影响更显著。产氢实验表明,各因素对产氢情况的影响显著,依次为:铁>镁>维生素液>微量元素液。当该菌利用缺铁培养基产氢时,其累计产氢量仅为44 mL/L ,铁元素的缺乏严重影响该菌的产氢活动。 相似文献