Study On The PHAs Biosynthesis Bacteria In Mangrove Soil

PHAs biosynthesis bacteria in samples of 6 mangrove soils were investigated by isolation and Fourier Transform InfraRed Spectroscopy (FT-IR) detection. Numbers of the PHAs accumulating bacteria were between 103-106 cfu/g dry soil, accounted for 1.5‰-317.3‰of heterotrophic bacteria in mangrove soil. Difference of distribution of PHAs accumulating bacteria in various mangrove soils was significant. Numbers of the PHAs accumulating bacteria in mangrove soil were affected by available phosphorus, organic matter, total nitrogen and carbon/nitrogen ratio. Numbers of PHAs accumulating bacteria were positively correlated to available phosphorus; When organic matter and total nitrogen were low , number of PHAs accumulating bacteria was positive correlated to the organic matter and total nitrogen concerntration; When organic matter and total nitrogen were high (organic matter≥38.3 g·kg -1, total nitrogen≥0.3g·kg -1), number of of PHAs accumulating bacteria was positive correlated to carbon/nitrogen ratio. There are more bacteria that produce short-chain-length PHAs or containing short-chain-length and medium-chain-length PHAs, each was about 40% of total PHAs accumulating bacteria., while mcl-PHAs accumulating bacteria was 17.8%. Most of the bacteria accumulated low yield of PHA, with the percentage of 79.9%.PHAs accumulating bacteria in mangrove soils were studied on culture-independent, level as well. A method of SDS-GITC-PEG-Resin Adsorption was established for extraction DNA from mangrove soil that suited for PHAs synthase gene PCR amplification. PHAs synthase genes could be detected using template DNA from mangrove soil after optimizing amplification system. Using a rapid method of FT-IR directly screening PHAs synthesis clones grown on glucose and minerals culture medium, thirty one positive clones were selected out from mangrove soil metagenome library which contained 7114 clones.