Isolation and characterization of an alkaline protease from the marine shipworm bacterium
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Bacterial isolates from the gland of Deshayes of the marine shipworm (Psiloteredo healdi) produced extracellular protease activity when cultured with 1% cellulose. A protease with a relative molecular mass of 36,000 daltons as determined by SDS-PAGE and a pI of 8.6 was isolated from the medium and purified to electrophoretic homogeneity. No carbohydrate appeared to be associated with the protein. The enzyme was activated and stabilized by relatively high salt concentrations (>0.2M). Below 0.1M salt, significant protein aggregation occurred, as well as autohydrolysis of the protease, both of which resulted in the loss of activity. The specific activity of the enzyme was 65,840 proteolytic units/mg with azocasein substrate of optimal temperature (42°C), pH (9.0), and salt concentration (0.20M NaCl). The activity was stable up to 40°C, from pH 3.0 to pH 11.9, and from 0.1M to 3.5M NaCl. These stabilities, as well as the protease's stability in the presence of chelators, oxidizing agents, and heavy metals, suggest the enzyme has potential for use in relatively low temperature (40°C) industrial applications.
KeywordsEnzyme Cellulose Heavy Metal Molecular Mass Salt Concentration
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- 5.Dubois M, Gilles KA, Hamilton JK, Rebers PA, Smith F (1956) Colorimetric method for determining sugars and related substances. Anal Chem 28:350–356Google Scholar
- 7.Gianazza E, Righetti PG (1979) Facts and artifacts in isoelectric focusing. In: Redola BJ (ed) Electrophoresis. Berlin, New York: Walter de, Gruyter, pp 129–140Google Scholar
- 8.Grant WD, Mwatha WE, Jones BE (1990) Alkaliphiles: ecology, diversity and applications. FEMS Microbiol Rev 75:255–270Google Scholar
- 9.Greene RV, Freer SN (1986) Growth characteristics of a novel nitrogen-fixing cellulolytic bacterium. Appl Environ Microbiol, 52:982–986Google Scholar
- 11.Greene RV, Cotta MA, Griffin HL (1990) A novel, symbiotic bacterium isolated from marine shipworm secretes proteolytic activity. Curr Microbiol 19:353–356Google Scholar
- 14.Kirk RE, Othmer DE (1980) Enzyme detergents and industrial enzymes. In: Kirk-Ozhzaer encyclopedia of chemical technology, 3rd edn, Vol. 9. New York: John Wiley & Sons, pp 138–224Google Scholar
- 19.Waterbury JB, Calloway CB, Turner RD (1983) A cellulolytic nitrogen-fixing bacterium cultured from the gland of Deshayes in shipworm (Bivalvia: Teredinidae) Science 221:1401–1403Google Scholar
- 20.Waterbury JB, Calloway CB, Turner RD (1989) Bacteria for cellulose digestion. U.S. Patent Number 4,861,721Google Scholar
- 21.Whitaker JR (1972) Principles of enzymology for the food sciences. New York: Marcel Dekker, IncGoogle Scholar
- 22.Williams KW, Soderberg L (1979) A carrier ampholyte for isoelectric focusing. International Laboratory, Jan/FebGoogle Scholar
- 23.Zaborsky OR, Attaway DH, Mitsui A (1990) Japanese marine biotechnology: new opportunities for industrial microbiology. SIM News 40:45–51Google Scholar