The aim of this work was to establish optimal conditions for the maximum production of endo-beta-1,4 mannanases using cheaper sources. Eight thermotolerant fungal strains were isolated from garden soil and compost samples collected in and around the Gulbarga University campus, India. Two strains were selected based on their ability to produce considerable endo-beta-1,4 mannanases activity while growing in liquid medium at 37 degrees C with locust bean gum (LBG) as the only carbon source. They were identified as Aspergillus niger gr and Aspergillus flavus gr. The experiment to evaluate the effect of different carbon sources, nitrogen sources, temperatures and initial pH of the medium on maximal enzyme production was studied. Enzyme productivity was influenced by the type of polysaccharide used as the carbon source. Copra meal defatted with n-hexane showed to be a better substrate than LBG and guar gum for endo-beta-1,4 mannanases production by A. niger gr (40.011 U/ml), but for A. flavus gr (33.532 U/ml), the difference was not significant. Endo-beta-1,4 mannanases produced from A. niger gr and A. flavus gr have high optimum temperature (65 and 60 degrees C) and good thermostability in the absence of any stabilizers (maintaining 50% of residual activity for 8 and 6 h, respectively, at 60 degrees C) and are stable over in a wide pH range. These new strains offer an attractive alternative source of enzymes for the food and feed processing industries.

Alpha-galactosidase from Aspergillus oryzae was immobilized on chitosan beads using glutaraldehyde as a cross-linking agent. The general properties of free and immobilized enzymes were determined. The optimum pH for the free and immobilized enzymes was 4.8 and 4.6 respectively. The optimum temperature for the free enzyme was 50 degrees C, whereas that of immobilized enzyme was increased to 56 degrees C. Kinetic parameters were determined with synthetic substrate (p-nitrophenyl alpha-D-galactopyranoside) and raffinose. Immobilized enzyme showed a higher Km and a lower Vmax than the free enzyme. The immobilized enzymes were used in batch, repeated and continuous mode. A level of 92% hydrolysis was observed at a flow rate of 60 ml/h. The immobilized enzyme was used repeatedly ten times without any change in the performance of the immobilized enzyme in fluidized-bed reactor. The results obtained are of considerable interest for industrial purposes.

Background α-Galactosidase is widely used in various biotechnological applications such as food processing, beet sugar, the pulp and paper industries, synthesis of oligosaccharides by trans-galactosylation, hydraulic fracturing of oil and gas wells, and medical applications. Results Screening and identification of fungi for α-galactosidase activity was performed. The isolate Penicillium sp. showed good α-galactosidase activity. α-Galactosidase production by the fungal strain Penicillium sp. cultivated in solid state fermentation (SSF) conditions using copra mannan extract as nutrient medium was investigated. The maximum α-galactosidase activity of 5.391 U/mL was obtained in defatted copra meal (dFCO) as carbon source, which is 2–3% greater as compared with commercial mannans and unprocessed copra meal. The highest product yield of α-galactosidase was obtained with media containing yeast extract (6.672 U/ml) as organic nitrogen and ammonium nitrate (6.325 U/ml) and as inorganic nitrogen source with media pH 5.5, and the time course of enzyme production was at the 5th day of fermentation, respectively. The optimum pH of α-galactosidase was obtained at pH 5 and optimum temperature at 60 °C. The enzyme was stable between pH 4 and 6 and retained more than 50% of residual activity for an 8-h incubation period. The Ca+2 ions enhanced the enzyme activity and Mn+2 ions have not altered the enzyme activity, whereas Hg+2 strongly inhibited the enzyme activity. Conclusions The findings of present investigations on α-galactosidase are of particular interest for its application in the food processing industry.

Background: Alkali metals such as lithium nitrate due to its properties have found their application in industries. However, reports of acute toxicological impact of lithium nitrate on aquatic animals are largely not available in the literature. Objective: With this interest, we have assessed the impact of LiNO 3 on Catla catla, a freshwater fish widely consumed. Materials and Methods: In this study, LC 50 of LiNO 3 was determined to be 5ppm, for 24 h. Following this, 1/10 th of the LC 50 levels of LiNO 3 (0.5ppm) was chosen for acute investigation of 96 h. Results: The results demonstrated increase in serum aspartate transaminase (AST), alanine transaminase (ALT) and lactate dehydrogenase (LDH) in treated fish. Further examinations disclosed changes in antioxidant enzyme systems with remarkable changes in the serum catalase (CAT) and superoxide dismutase (SOD) contents, with elevation in malondialdehyde (MDA). The investigation found increased glutamate levels in the brain tissue of treated groups, demonstrating tissue damage. Conclusion: The study underlines the toxicological impact of LiNO 3 and role of certain potential biomarkers which determine the impact of these toxicants in aquatic environment.

Xenobiotics from chemicals to plastics have seriously interfered with the biological process of living system. Their impact on aquatic ecosystem, fish in precise is studied with significant interest. However, studies on impact of xenobiotics on marine fish are limited. This literature review integrates and summarizes the impact of xenobiotics on marine fish. The review tries to understand the impact of macro and micro litters, microplastic, metals like mercury and nanoparticles. Finally, we conclude with the ways to regulate the presence and distribution of these xenobiotics in marine environment.