Abstract: We used filter paper method to investigate the quorum sensing inhibitory activity and culture condition of a marine Actinomycetes Streptomyces parvulus（HY026）that was isolated from Lianyungang surface water in our previous study. It was found that,the metabolites of S. parvulus（HY026）significantly inhibited the violacein production in the quorum sensing reporter bacterium Chromobacterium violaceum 12472,showing the strong inhibition to quorum sensing activity. The carbon and nitrogen sources of HY026 medium were optimized by single factor experiment. It was revealed that the quality and quorum sensing inhibitory activity of the HY026 crude extract were the highest when corn meal was used as carbon source,and the quality and activity of the crude extract were the highest when soybean meal was used as nitrogen source. According to the results of the single factor experiment,corn meal and soybean meal were selected as the best carbon and nitrogen sources,and 4 factors,including salinity and potassium hydrogen phosphate,were used to carry out L16（4⁵）orthogonal experiment. The quality and quorum sensing activity of the crude extracts from each treatment were analyzed. The order of importance of the four factors was as potassium hydrogen phosphate > salinity > corn flour > soybean flour. The optimal medium recipe was potassium hydrogen phosphate 1.0 g/L,salinity 34.0 g/L,corn flour 20.0 g/L and soybean flour 5.0 g/L. The quality and quorum sensing inhibitory activity of the crude extracts from S. parvulus HY026 fermentation broth increased by 398% and 19%,respectively,when cultured in this optimal recipe.

Key words: marine microorganisms, Streptomyces parvulus, quorum sensing, condition optimization