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Background: Proteases from bacteria are among the most important hydrolytic enzymes that have been studied due to their extracellular nature and high yield of production. Of these, alkaline proteases have potential for application in detergent, leather, food, and pharmaceutical industries. However, their usefulness in industry is limited by low activity and stability at high temperatures, extreme pH, presence of organic solvents and detergent ingredients. It is therefore very crucial to search for new alkaline proteases with novel properties from a variety of microbial sources. Results: In the present study, 21 Bacillus species isolated from organic waste sites were screened for proteolytic activity on casein agar. Bacillus brevis MWB-01 exhibited highest proteolytic activity with a clear zone diameter of 35 mm. Production of protease from B. brevis MWB-01 was investigated in optimized media after 48 h of cultivation with shaking (180 rpm) at 37°C. The protease was partially purified in a two-step procedure using ammonium sulphate precipitation and gel filtration chromatography on Sephadex G-200 column. The enzyme was purified 2.1-fold with yield of 4.6%. The purified protease had optimum temperature of 40°C with relative activity of about 50% at 50°C and was uniquely stable up to 60°C after 30 min of incubation exhibiting 63% residual activity. The enzyme had optimum pH of 8.0 and remarkably showed relative activity above 70% at pH 9.0 to 11.0 and 53% at pH 12.0, respectively and was very stable over a wide pH range (6.0 to 12.0). Ca 2+ and Mn 2+ increased protease activity with 9.8% and 3.5%, respectively; Hg 2+ and Zn 2+ strongly inhibited protease activity by 89% and 86%. The almost complete inhibition of the enzyme by phenylmethylsulphonyl fluoride (PMSF) and ethylene diamine tetra acetic acid (EDTA) confirmed the enzyme as a serine metalloprotease. The enzyme had highest compatibility with Sunlight, a commercial laundry detergent.

Twelve strains of Bacillus licheniformis isolated from traditionally fermented African locust bean (Parkia biglobosa) were evaluated in respect to production of protease on skim milk agar. B. licheniformis LBBL-11 exhibited the highest proteolytic activity with an average area of clear zone measuring 960 mm 2 . Production of protease from B. licheniformis LBBL-11 was further studied by growing the strain on nutrient broth. Maximum protease production was 18.4 U/mL at 48 h of growth, which coincided with the end of exponential phase. The protease from this Bacillus sp. had optimum pH of 8.0 and was stable over a wide pH range of 5.0-11.0. The optimum temperature for the protease activity was 60C. The enzyme was 95% stable at 60C after 60 min of incubation. These properties indicate possible application of B. licheniformis LBBL-11 as potential starter culture for the fermentation of African locust bean under controlled conditions of temperature and pH. PRACTICAL APPLICATIONSAfrican locust bean seeds (Parkia biglobosa) are rich in protein and usually fermented to a tasty food condiment (iru) used as flavor intensifier for soups. This is highly consumed in developing and under developed countries

The non-enzymatic and enzymatic antioxidant defense systems play a major role in detoxification of pro-oxidant endobiotics and xenobiotics. The possible involvement of beetle non-enzymatic [α-tocopherol, glutathione (GSH), and ascorbic acid] and enzymatic [catalase (CAT), superoxide dismutase (SOD), peroxidase (POX), and polyphenol oxidase (PPO)] antioxidant defense system on the insecticidal activity of synthetic insecticides (cypermethrin, 2,2-dicholorovinyl dimethyl phosphate, and λ-cyhalothrin) and ethanolic plant extracts of Tithonia diversifolia, Cyperus rotundus, Hyptis suaveolens leaves, and Jatropha Curcas seeds was investigated. 2,2-Dicholorovinyl dimethyl phosphate (DDVP; 200 ppm, LC 50 = 13.24 ppm) and T. diversifolia (20,000 ppm) resulted in 100% beetle mortality at 96-hour post-treatment. The post-treatments significantly increased the beetle α-tocopherol and GSH contents. Activities of CAT, SOD, POX, and PPO were modulated by the synthetic insecticides and bioinsecticides to diminish the adverse effect of the chemical stresses. Quantitative and qualitative allelochemical compositions of bioinsecticides and chemical structure of synthetic insecticides possibly account and for modulation of their respective enzyme activities. Altogether, oxidative stress was enormous enough to cause maladaptation in insects. This study established that oxidative imbalance created could be the molecular basis of the efficacy of both insecticides and bio-insecticides. Two, there was development of functional but inadequate antioxidant defense mechanism in the beetle.