title: Diversity of cultivable protease-producing bacteria in sediments of Jiaozhou Bay, China.
abstract: Although protease-producing bacteria are key players in the degradation of organic nitrogen and essential for the nitrogen recycling in marine sediments, diversity of both these bacteria and their extracellular proteases is still largely unknown. This study investigated the diversity of the cultivable protease-producing bacteria and their extracellular proteases in the sediments of the eutrophied Jiaozhou Bay, China through phylogenetic analysis and protease inhibitor tests. The abundance of the cultivable protease-producing bacteria was up to 10(4) cells/g in all six sediment samples. The cultivated protease-producing bacteria mostly belonged to the phyla Proteobacteria and Firmicutes with the predominant genera being Photobacterium (39.4%), Bacillus (25.8%), and Vibrio (19.7%). Protease inhibitor tests revealed that extracellular proteases secreted by the bacteria were mainly serine proteases and/or metalloproteases with relatively low proportions of cysteine proteases. This study represents the first comprehensive analysis on the diversity of protease-producing bacteria and their extracellular proteases in sediments of a eutrophic bay.
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University Jinan, China ; Marine Biotechnology Research Center, Shandong University Jinan, China.
authors.forename: Xi-Ying
authors.initials: XY
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University Jinan, China ; Marine Biotechnology Research Center, Shandong University Jinan, China.
authors.forename: Xiao-Xu
authors.initials: XX
authors.lastname: Han
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University Jinan, China ; Marine Biotechnology Research Center, Shandong University Jinan, China.
authors.forename: Xiu-Lan
authors.initials: XL
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University Xiamen, China.
authors.forename: Hong-Yue
authors.initials: HY
authors.lastname: Dang
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University Jinan, China ; Marine Biotechnology Research Center, Shandong University Jinan, China.
authors.forename: Bin-Bin
authors.initials: BB
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University Jinan, China ; Marine Biotechnology Research Center, Shandong University Jinan, China.
authors.forename: Qi-Long
authors.initials: QL
authors.lastname: Qin
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University Jinan, China ; Marine Biotechnology Research Center, Shandong University Jinan, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University Jinan, China ; Marine Biotechnology Research Center, Shandong University Jinan, China.
authors.forename: Bai-Cheng
authors.initials: BC
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University Jinan, China ; Marine Biotechnology Research Center, Shandong University Jinan, China.
authors.forename: Yu-Zhong
authors.initials: YZ
authors.lastname: Zhang
keywords: Jiaozhou Bay; diversity; extracellular proteases; protease inhibitor tests; protease-producing bacteria