High-yield production and biochemical characterization of α-galactosidase produced from locally isolated Penicillium sp.

Abstract

Abstract 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.