Optimization, purification and characterization of novel thermostable, haloalkaline, solvent stable protease from Bacillus halodurans CAS6 using marine shellfish wastes: a potential additive for detergent and antioxidant synthesis

Abstract

A protease producing marine bacterium, Bacillus halodurans CAS6 isolated from marine sediments, was found to produce higher enzyme by utilizing shrimp shell powder. Optimum culture conditions for protease production were 50 °C, pH 9.0, 30 % NaCl and 1 % shrimp shell powder (SSP) and the protease purified with a specific activity of 509.84 U/mg. The enzyme retained 100 % of its original activity even at 70 °C, pH 10.0 and 30 % NaCl for 1 h. The purified protease exhibited higher stability when treated with ionic, non-ionic (72-94 %) and commercial detergents (76-88 %), and organic solvents (88-126 %). Significant blood stain removal activity was found with the enzyme in washing experiments. The culture supernatant supplemented with 1 % SSP showed 93.67 ± 2.52 % scavenging activity and FT-IR analysis of the reaction mixture confirmed the presence of antioxidants such as cyclohexane and cyclic depsipeptide with aliphatic amino groups. These remarkable qualities found with this enzyme produced by Bacillus halodurans CAS6 could make this as an ideal candidate to develop the industrial process for bioconversion of marine wastes and antioxidant synthesis.

Purification and Characterization of Halophilic Organic Solvent Tolerant Protease from Marine Bacillus sp. APCMST-RS7 and Its Antioxidant Potentials

“…The highest IC 50 (1.4 mg/ml) was obtained with B. cereus SV1 hydrolysate [19]. Similarly Annamalai et al [37] reported that, the alkaline protease from B. halodurans CAS6 had attained 96 % maximum antioxidant activity using shrimp shell as a substrate. From the results obtained, it may be inferred that the reducing power of shrimp shell hydrolysate increased with increasing concentrations of samples (0.25-2 mg/ml).…”

“…Similar to the present investigations, alkaline serine protease from various Bacillus sp. showed better blood cleaning ability [7,21,37,38].…”

“…However, reports related to the protease production by candidate bacterium using crustacean shell waste as a substrate were very much limited. The maximum protease production attained by applying the proteolytic bacterium such as B. subtilis A26 [39], B. licheniformis RP1 [40], B. cereus TKU006 [5], B. halodurans CAS6 [37] and Virgibacillus halodenitrificans RSK CAS1 [38] by using crustacean shell waste as a substrate. Therefore, the present investigation clearly showed that, Bacillus sp.…”

Mediterranean agro‐industrial wastes as valuable substrates for lignocellulolytic enzymes and protein production by solid‐state fermentation

“…Triton X‐100 is a non‐ionic surfactant, and it can improve the solubilization of the enzyme from the solid substrate to the solution. Sodium chloride was used to increase the stability of the enzyme, based on literature . Subsequently, the extract was filtered through a nylon net and the liquid fraction was centrifuged at 6000 × g for 10 min.…”

Isolation, purification and partial characterization of thermostable serine alkaline protease from a newly isolated Bacillus thuringinsis-SH-II-1A

“…Isolated protease has shown good stability and compatibility in the presence of detergent Surf excel. The enzyme retained more than 60% activity with most of the detergents tested even after 2.5 h incubation at 45°C after the supplementation of CaCl 2 and glycine (Annamalai et al, 2013). High activity alkaline protease was reported from Conidiobolus coronatus showing compatibility at 50°C, in the presence of 25 mM CaCl 2 , with a variety of commercial detergents.…”