[Factors restricting growth of heterotrophic bacteria in the water body of West Lake, Hangzhou].

Restricting factors of bacteria growth were studied by pure culture and natural culture test. The results showed that organic carbon source available for bacteria was more important than (NH4)2SO4 and KH2PO4, while higher pH, and rich biomass of phytoplanktons and zooplanktons in the water restrained the growth of heterotrophic bacteria. Under natural culture experiment, Azotobacter increased after 0.5% glucose was added, and a lot of mildew grew after adding 0.5% glucose with 0.1% (NH4)2SO4 and 0.1% KH2PO4, while Pseudomonas enriched 30-57% after adding 0.01% beef extract. It was also showed that bacteria growth potentiality in natural water could reach to 10(5) cfu.ml-1.