Characterization of β-galactosidase from lactose utilizing yeast isolated from murcha

Here goes below an abstract of Saket Adhikari and Krishna Om Shrestha who pursued their thesis conducted under my supervision (and Prof. Agrawal) as a partial fulfillment of their B. Sc. Biochemistry degree from Universal Science College, Pokhara University. They jointly worked to characterize β-galactosidase from lactose utilizing yeast isolated from murcha (Yeast Cakes) from Kathmandu valley. This endeavor followed the findings of previous student, Manindra Lal Shrestha for his thesis work. With his work we discovered the abundance of lactose utilizing yeasts in Nepalese murcha samples collected from different parts of Nepal; the paper is accepted in the second volume of Nepalese Journal of Microbiology (NJM).

Abstract
Lactose utilizing yeasts have a potential application in the lactose pollution management in brewery and dairy industries as the organisms can grow at environmental conditions well. Eleven strains of lactose positive yeast were isolated from murcha samples collected from local markets in Kathmandu. Because of highest lactose positive activity among the isolated strains, L4 was selected for production, partially purification and characterization of β-galactosidase. Mass culture of the strain was treated with 2% (v/v) Chloroform and the enzyme was purified with Acetone precipitation method to 7.7 fold activity. Specific activity of the enzyme was found to be 0.054 nmol/min/mg of protein, and Km value for O-nitrophenyl-β-D-galactopyranoside was 8.798 mM. Optimum temperature and pH were determined to be 37°C and 6.6 respectively with the reaction time period 180 min.