Screening and diversity of lipase-producing bacteria in the sediments of Bohai Sea

[Objective] To uncover the diversity of cultivable lipase-producing bacterial isolated from the sediments of Bohai Sea and expand our knowledge on lipase-producing bacteria. Through screening efficient lipase production strains to expanding the marine lipase-producing microorganism resources.【Methods】 The lipase-producing bacteria were isolated by using tween-80 plate and tributyrin plate from 8 sediment samples of the Bohai Sea. The diversity of these bacteria was evaluated through phylogenetic analyses based on 16S rRNA gene sequences. Using the p-nitrophenol method to detect extracellular lipase activity and select high lipase producing strains. [Results] A total of 51 lipase-producing strains were isolated from 8 sediment samples. The isolates were classified into 8 genera of three phyla including Bacteroidetes, Proteobacteria, and Firmicutes, with Pseudoalteromonas (35.2%), Marinobacter (23.5%) and Sulfitobacter (17.6%) as the dominant. Enzyme activity test showed that all the strains were able to secrete lipase, and a lipase-producing strain Marinobacter sp.70623 possesses the highest lipase activity of 42.4 U/mL. [Conclusion] The cultivable lipase-producing bacteria isolated from the sediment of Bohai Sea are abundant with Pseudoalteromonas, Marinobacter and Sulfitobacter bacteria as the dominant groups, all the tested strains possess lipase activity, and the highest lipase activity producing strain Marinobacter sp. 70623 was obtained in this study