The use of nug meal as a low-cost substrate for the production of alkaline protease by the alkaliphilic Bacillus sp. AR-009 and some properties of the enzyme

Bacillus sp AR-009 produced appreciable extracellular alkaline protease when grown using nug meal (a byproduct of oil extraction from Guizotia abyssinica seeds) as the sole nitrogen source. The enzyme had an optimum pH of 9.5–11.5 and was stable in the pH range of 5–12. Its optimum temperature was 55°C in the absence of calcium and 65°C in the presence of calcium. At 50°C and above calcium was required for thermal stability. The enzyme was completely inhibited by PMSF suggesting that it is a serine protease.