E有机酸对甲烷利用菌Methylosinus trichosporium IMV3011生物合成聚-3-羟基丁酸酯的影响(英文)

Effect of Organic Acids on Biosynthesis of Poly-3-Hydroxybutyrate of Methylosinus Trichosporium IMV3011

为了降低聚-3-羟基丁酸酯(PHB)的生产成本,利用甲烷和甲醇生长的甲烷利用菌是具有研究价值的一类菌种.文章针对如何克服甲烷利用菌IMV3011积累PHB过程中受到制约的因素进行了考察,以改善此菌种生产PHB的能力.研究发现,通过添加适量的三羧酸(TCA)循环的抑制剂——苹果酸可以达到很高PHB产量的目的.在细胞进行两阶段培养过程中,营养平衡和营养受限培养各进行24h,即加入不同浓度的苹果酸(前者控制在5.7×10-4g/L,后者控制在0.03g/L),可以使PHB的积累量达到55%(未添加只能达到40%).实验还通过对PHB合成中所需的酶的活性研究,从一定程度上证明了适当的抑制三羧酸循环对保持PHB合成的酶系的活性将更有利于PHB的合成.

Methanotrophs using methane and methanol as their source of carbon and energy will be an optimal strain for poly-3-hydroxybutyrate （PHB） biosynthesis in less expensive production. Then the study was carried on to improve the important limiting factors for the application of synthesis of PHB in methanotrophs Methylosinus trichosporium IMV3011 （ IMV3011 ）. It has been found that malic acid, an important intermediate in TCA cycle, is a favorable organic acid for the synthesis of PHB intracellularly. When the cell was cultivated for 24 h under different condition, the addition of malic acid with appropriate concentration （5.7 × 10 ^-4g/L in nutrients sufficient condition in the first stage and 0. 03g/L in nutrients deficiency condition in the second stage） would improve the mass of PHB in biomass to 55% in contrast to that with no addition （40%）. Combined with the activity of enzymes performed in PHB cycle, it was concluded that the optimal way to produce PHB in high yield is to inhibit tricarboxylic acid （TCA） cycle to certain extent and not decrease the activities of key enzymes in synthesis of PHB.