Srabanti Basu

Title : Lactase and amylase from the seeds of Artocarpus heterophyllus (jack fruit)

Abstract:

Biocatalysts are natural substances that include enzymes and whole cells to carry out different biochemical reactions. Enzymes have become important tools for production of food and pharmaceutical products as they offer less energy requiring and less polluting methods compared to conventional processes. Amylase and lactase are two enzymes widely used in food industry for bread, wine, cheese, and other products. The present study reports the recovery of appreciable amount of lactase and amylase from the seeds of jack fruit (Artocarpus heterophyllus). The seed extract hydrolyzed almost 90% of 2 % (w/v) at pH 5.5 in 3h at 50°C. It hydrolyzed 75% of milk sugar present in 100 mL of pasteurized cow milk at 40°C in the same time interval. The extract possessed amylase activity too and hydrolyzed raw and gelatinized cereal and tuber starches obtained from corn, rice, gram, wheat and potato. The amylase could hydrolyze both amylopectin and starch with the same ease. Both lactase and amylase were optimally active at a pH and temperature range of 5.0-7.5 and 45-60°C respectively. Both were stable in the pH range of 4-8 upto 60°C. Both the enzymes were resistant to the action of several proteases. Hg²⁺ and Ag⁺ completely inhibited the activities of both the enzymes. Lactase was purified by ethanol precipitation, followed by Ammonium sulphate precipitation, ion exchange chromatography (DEAE Sephadex), size exclusion chromatograohy (Sephacryl S-300) and SDS PAGE. Activity staining by x-gal on Native gel was also performed. Lyophilized seed powder and extract remained stable till one year of the study period when stored at 4°C.  

Audience take-away:

• The work describes extraction, characterization and purification of two industrially important enzymes from a commonly available tropical plant. Other plants can be explored for the same or other industrially important enzymes.
• The research can be expanded to large scale production of the enzymes.
• Jack fruit seeds are edible. Therefore the extract can be applied safely in food and pharmaceutical industries.
• Lactase described here is resistant to proteases. It can be directly supplemented in milk formulations for lactose intolerant people.

Biography:

Dr. Srabanti Basu is a professor in the department of biotechnology, Heritage Institute of Technology, Kolkata. She did her M.Sc. and Ph.D. in Biochemistry from the University of Calcutta. She started her career as a journalist in The Telegraph, a leading daily of Kolkata for the science page. After two years, she joined her present institute as an assistant professor (then lecturer). She received Fulbright Nehru fellowship and several other international and national awards for her contribution to biotechnology research. Environmental biotechnology is her special area of interest. She has 26 publications in peer-reviewed journals.