窖泥功能菌与产酯菌共酵生产性试验(提高泸州曲酒厂名优酒比率的研究鉴定材料之三)

采用窖泥功能菌与产酯微生物共酵,提高泸型曲酒名优酒比率的研究,于1987年4月在泸州曲酒厂科研所小窖内进行了模拟试验。全部试验窖的酒都比对照窑好,总酯和已酸乙酯含量都有较明显的增加。在此基础上,我们选择了3个方案,于同年6月在泸州曲酒厂酿酒实验中心生产窖池中进行了连续3排的生产性试验,于1988年1月初结束。

Production of Poly(3-Hydroxybutyrate)by Fed-Batch Culture of Alcaligenes Eutrophus at Phosphorus Limitation in 50 L fermenter

Poly(3-hydroxybutyrate) (PHB) is an intracellular carbon and energy storage material accumulated by many kinds of microorganism under unfavorable growth conditions. For the production of PHB, Alcaligenes eutrophus has been widely used because it is easy to grow, and its physiological and biochemical changes during the PHB synthesis is understood in details. A very high concentration and productivity of PHB could be obtained by fed-batch culture of Alcaligenes eutrophus with phosphate limitation in 50 L fermenter.

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^-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.

Production of Poly（3-hydroxybutyrate-co-3-hydroxyhexanoate） by Recombinant Pseudomonas stutzeri 1317 from Unrelated Carbon Sources

Synthetic biology promises to simplify the construction of metabolic pathways by assembling the de- tached modules of the whole pathway. This gives new approaches for the microbial production of industrial products such as polyhydroxyalkanoates （PHA）. In this study, to produce poly（3-hydroxybutyrate-co-3-hydroxyhexanoate） （PHBHHx） by Pseudomonas stutzeri 1317 from unrelated carbon sources such as glucose, the phaCl-phaZ-phaC2 operon of P. stutzeri 1317 was knocked out to generate the PHA deficient mutant P. stutzeri 1317LF. Then three modules containing phaCahAReBRe, phaCahBReGep and phaCAhPah were introduced into P. stutzeri 1317LF separately The shake flask results indicated that the precursor supply and PHA synthase activity were the vital factors for the PHBHHx accumulation of P. stutzeri 1317LF. Furthermore, the PHBHHx accumulation of the recombinants from different carbon resources were performed. The highest PHBHHx content was 23.7% （by mass） with 58.6% （by mole） 3HB fraction. These results provide basis for further improving the PHBHHx accumulation of P. stutzeri from unrelated carbon sources.

Selection of Strains Producing Lipase with Transesterification Activity and Its Characterization

The interest for lipase production is due to the ability of this enzyme to catalyze some reactions, such as the transesterification. Although industrial biodiesel is produced chemically, there are several problems associated with this technology that can be prevented through the use of lipases. The present work aimed to select microorganisms with potential for production of lipase with transesterification activity. The lipase from Burkholderia cepacia was the one with the most promising results for this type of reaction, showing results of hydrolytic activity at 37 ℃and pH 8.0. The pH and volume of crude enzyme extract that showed favorable for synthesis ofbiodiesel is at about pH 6.0 and 3.75 mL, respectively, which represents approximately 42% of water in the system, ensuring the conversion of nearly 60% to biodiesel.