Activation of proteases in an anaerobic sulphidogenic bioreactor.
Activities of proteases were stimulated by specific sulphur metabolites during the enhanced hydrolysis of complex polymeric organic carbon in an anaerobic sulphidogenic environment. While sulphate at 1000 mg l(-1) inhibited proteases by 50%, there was a 2.5-fold increase in activity of proteases by added sulphite and a 3.6-fold increase from added sulphide. Two hypothetical models are proposed. First the sulphur species, sulphite (HSO3-) and sulphide (HS-), liberated at different times during the sulphate reduction process, directly activate the proteases, which are associated with the organic particulate matter, leading to a subsequent enhancement of hydrolysis of polymeric material. Second, they indirectly activate the proteases by neutralising the cations on the floc surface disrupting the integrity of the organic particulate floc therebye releasing further entrapped enzymes from the organic particulate matter.
Whiteley
Chris
C
Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown 6140, South Africa. c.whiteley@ru.ac.za
Pletschke
Brett
B
Rose
Peter
P
Tshivhunge
Sylvia
S
Watson
Shaun
S
Whittington-Jones
Kevin
K
D001421:Bacteria, Anaerobic / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods; D010450:Endopeptidases / Q000737:chemistry* / Q000378:metabolism; D004789:Enzyme Activation; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D013457:Sulfur Compounds / Q000737:chemistry* / Q000378:metabolism*
D012722:Sewage; D013457:Sulfur Compounds; D010450:Endopeptidases