Partial characterization Of an alkalophilic extracellular Crude pectinases from a bacillus Polymyxa strain

Abstract

A mesophilic spore forming isolate from the soil of Um-Qais region, which could produce extracellular pectinases was tentatively identified as Bacillus polymyxa. This bacterium grew best at 37°C and pH 7.0 and was able to produce extracellular enzymes other than pectinases, e.g.: protease, amylases, and cellulases. The production of two pectolytic enzymes, pectin lyase and pectate lyase, by this organism was investigated. Pectin lyase production reached its maximum in 12h cultures, while pectate lyase reached its maximum production in 15h cultures. The optimum pH and optimum temperature for pectin lyase activity were 8.5 and 30°C, respectively, while for pectate lyase the optima were 9 and 30°C repectively. Chelating agents such as lmM EDTA caused a decrease in pectate lyase activity by about 48%, nitrilotriacetate (NTA) also caused a decrease in activity of pectin lyase and pectate lyase by about 35% and 53% respectively. Divalent ions such as, Co , Hg , Cu , and Fe inhibited pectin lyase activity at the concentration of lmM, while Mg+2, and Mn+2 stimulated the enzyme activity to about 105% and 140% respectively at the same concentration. Pectate lyase, was inhibited by Co+2, Hg+2, Cu+2 and Fe+3 at the concentration of lmM, while Mg+2, Zn+2, and Mn+2 stimulated its activity to about 106%, 186%, and 230%, respectively at the same concentration.