Hyper Production of Β‐Galactosidase From Newly Isolated Strain of Aspergillus nidulans

Abstract

AbstractSeveral Aspergillus species were isolated from soil samples collected from local dairy farms and screened for the production of β‐galactosidase. The potent isolate was identified as Aspergillus nidulans on the basis of microscopic and phenotypic characteristics. The production of β‐galactosidase from A. nidulans was optimized in batch fermentation using one‐variable‐at‐a‐time approach. Evaluation of process parameters indicated that A. nidulans produced high titer of β‐galactosidase at 35°C after 10.0 days of fermentation. It was found that A. nidulans is capable of releasing 60.0 U mg−1 of β‐galactosidase at pH 3.0. Among various carbon sources xylose (0.5%) showed maximum enzyme production. Glucose (1.0%), tri‐sodium citrate (0.7%), and potassium dihydrogen phosphate (0.3%) indicated positive affect by inducing the culture for maximum synthesis of β‐galactosidase. Various organic and inorganic nitrogen sources were also tested and it was noticed that peptone (0.5%), yeast extract (0.5%), ammonium sulfate (0.2%), and ammonium nitrate (0.2%) improved the production of β‐galactosidase. These results suggested the feasibility of A. nidulans for the large scale production of β‐galactosidase.Practical ApplicationsBeta galactosidase has potential applications in food processing industry and enzymatic hydrolysis of lactose is best process as compared to high temperature and acids treatment as it retains maximum quality of product. This enzyme is used to obtain the hydrolyzed lactose from milk and milk whey for utilization in bakery products, animal feeds and as a sugar source for several fermentation products. This enzyme is also used in ice creams and condensed dairy products to avoid lactose crystallization. The syrup produced by lactose conversion using enzyme hydrolysis is used in dairy and soft drink industries. In pharmaceutical industry, it is used to produce lactose‐free milk for lactose intolerant consumers who are unable to digest the milk lactose.