ORIGINAL PAPER Production and partial characterization of chitinase from a halotolerant Planococcus rifitoensis strain M2-26

Abstract This paper is the first to investigate the pro-duction and partial characterization of the chitinase enzyme from a moderately halophilic bacterium Planococcus rifi-toensis strain M2-26, earlier isolated from a shallow salt lake in Tunisia. The impact of salt, salinity concentration, pH, carbon and nitrogen sources on chitinase production and activity have been determined. This is the first report on a high salt-tolerant chitinase from P. rifitoensis, since it was active at high salinity (from 5 to 30 % NaCl) as well as in the absence of salt. This enzyme showed optimal activity at 70C and retained up to 82 and 66 % of its original activity at 80 or 90C, respectively. The activity of the enzyme was also shown over a wide pH range (from 5 to 11). For characterization of the enzyme activity, the chi-tinase secreted in the culture supernatant was partially purified. The preliminary study of the concentrated dia-lysed supernatant on native PAGE showed at least three chitinases produced by strain M2-26, with highest activity approximately at 65 kDa. Thus, the thermo-tolerant and high salt-tolerant chitinases produced by P. rifitoensis strain M2-26 could be useful for application in diverse areas such as biotechnology and agro-industry