Low cost single-step purification of endoglucanase from Aspergillus fumigatus ABK-9.

Low cost agro-waste was used as adsorption support for single-step purification of endoglucanase from the culture filtrate of A. fumigatus ABK-9. Among various agro-waste substrates, 1% NaOH pretreated rice bran was proved to be the best for adsorbing about 74.8 and 71.1% of endoglucanase at 4 °C and 10 °C respectively. Langmuir type adsorption isotherm at 4 °C showed maximum adsorption of enzyme at pH 5.0, which was in the range of optimum pH of the enzyme. The rice bran column bound enzyme was maximally eluted by a mixture of acetate buffer (0.05 M, pH 5.5) and ethanol (40%, v/v) at a ratio of 3:2 and a flow rate of 1 mL/min. A 5.52-fold purification of the enzyme was achieved from culture supernatant. The specific activity and recovery yield after purification were 294.0 U/mg and 40.15%, respectively, which were comparable with other contemporary protocols. The homogeneity of the enzyme was tested through sodium dodecyl sulphate polyacrylamide gel electrophoresis and a single band of 56.3 kDa was observed. Zymogram analysis finally confirmed the occurrence of endoglucanase in the single band.

Exploitation of fermented shrimp-shells hydrolysate as functional food: Assessment of antioxidant, hypocholesterolemic and prebiotic activities.

In the present study the bioactivities of chitooligosaccharides of fermented shrimp-shell hydrolysate (SSH) in respect to hypocholesterolemic, antioxidant and prebiotic activity were tested in male albino rat. Rats were treated with four different diets, viz., (i) cholesterol-rich (5%) basal diet (ChB), (ii) ChB+10% chitin, (iii) ChB+10% SSH and (iv) control group (without cholesterol). After 4 weeks of treatment, body mass index, liver weight, serum total cholesterol and LDL-cholesterol in groups (ii) and (iii) were decreased significantly than group (i). SSH supplementation significantly resists oxidative stress by reducing the thiobarbituric acid reactive substances and by increasing catalase, superoxide dismutase and free radical scavenging activity. The colonization of Lactobacillus and Bifidobacterium population in small and large intestine were more in group (iii) than other groups. Reduction of Clostridium perfringens population and non-significant changes of E. coli was also noted in SSH supplement group. Histological study revealed that the villus height and villus:crypt of the small intestine were increased significantly in SSH supplemented group (iii) without any diarrheal symptoms. The results demonstrated that the shrimp-shells hydrolysate has hypocholesterolemic effect, can resist lipid peroxidation and can influence the growth of health beneficial microbes, hence can be used as functional food for hypercholesterolemic patients.

Study on Thermodynamics and Adsorption kinetics of Purified endoglucanase (CMCase) from Penicillium notatum NCIM NO-923 produced under mixed solid-state fermentation of waste cabbage and Bagasse

In the current study, one thermostable endoglucanase was purified from Penicillium notatum NCIM NO-923 through mixed solid state fermentation of waste cabbage and bagasse. The molecular weight of the purified enzyme was 55kDa as determined by SDS polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme had low activation energy (Ea) of 36.39KJ mol-1 for carboxymethyl cellulose hydrolysis and the enthalpy and entropy for irreversible inactivation was 87 kJ mol −1 and 59.3 J mol −1 K−1 respectively. The enzyme was quite thermostable with a Tm value of 62.2˚C. The pKa1 and pKa2 of ionizable groups of the active sites were 2.5 and 5.3 respectively. Apparent Km, Vmax and Kcat of the enzyme were found to be 5.2 mg mL-1, 80 U/gds and 322.4 sec-1 respectively. The enzyme showed about 1.4 fold increased activity in presence of 10mM MgSO4. Adsorption of endoglucanase on Avicel at wide pH range was studied at different temperatures. Langmuir type adsorption isotherm at 10˚C showed maximum adsorption strength of enzyme at pH 3.0, which was in a range of optimum pH of the enzyme.