title: A novel sulfate-reducing bacteria detection method based on inhibition of cysteine protease activity.
abstract: Sulfate-reducing bacteria (SRB) have been extensively studied in corrosion and environmental science. However, fast enumeration of SRB population is still a difficult task. This work presents a novel specific SRB detection method based on inhibition of cysteine protease activity. The hydrolytic activity of cysteine protease was inhibited by taking advantage of sulfide, the characteristic metabolic product of SRB, to attack active cysteine thiol group in cysteine protease catalytic sites. The active thiol S-sulfhydration process could be used for SRB detection, since the amount of sulfide accumulated in culture medium was highly related with initial bacterial concentration. The working conditions of cysteine protease have been optimized to obtain better detection capability, and the SRB detection performances have been evaluated in this work. The proposed SRB detection method based on inhibition of cysteine protease activity avoided the use of biological recognition elements. In addition, compared with the widely used most probable number (MPN) method which would take up to at least 15days to accomplish whole detection process, the method based on inhibition of papain activity could detect SRB in 2 days, with a detection limit of 5.21×10(2) cfu mL(-1). The detection time for SRB population quantitative analysis was greatly shortened.
authors.affiliation: Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; University of the Chinese Academy of Sciences, 19 (Jia) Yuquan Road, Beijing 100039, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Qi
authors.affiliation: Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China. Electronic address: zhangdun@qdio.ac.cn.
authors.forename: Dun
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wan
mesh_terms: D002021:Buffers; D002384:Catalysis; D020134:Catalytic Domain; D003470:Culture Media / Q000737:chemistry; D057056:Cysteine Proteases / Q000737:chemistry*; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry*; D003901:Desulfovibrio / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli / Q000302:isolation & purification / Q000378:metabolism; D005978:Glutathione / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D010100:Oxygen / Q000737:chemistry; D010206:Papain / Q000737:chemistry; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000378:metabolism; D013431:Sulfates / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry; D016999:Sulfur-Reducing Bacteria / Q000302:isolation & purification* / Q000378:metabolism; D013696:Temperature; D044149:Vibrio alginolyticus / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D002021:Buffers; D003470:Culture Media; D015853:Cysteine Proteinase Inhibitors; D013431:Sulfates; D013440:Sulfides; D057056:Cysteine Proteases; D010206:Papain; D005978:Glutathione; D010100:Oxygen
keywords: Cysteine protease; Inhibition; S-sulfhydration; Sulfate-reducing bacteria