Arun Kumar Sharma1, ShreyaNegi1, Vinay Sharma1*, Jyoti Saxena2
1Department of Bioscience and Biotechnology, Banasthali University, Rajasthan, India.
2Department of Biochemical Engineering, Bipin Tripathi Kumaon Institute of Technology, Dwarahat, Uttrakhand India.
Prof. Vinay Sharma
Department of Bioscience and Biotechnology,
Banasthali University, Rajasthan, India.
Background: Proteases are crucial category of enzymes, account for the main global industrial market and are utilized in dairy industry, detergent industry, pharmaceutical, food processing and leather manufacturing. Objectives: The purpose of the present study was to identify the proteolytic soil fungal isolate by macroscopic and microscopic observations and to enhance the extracellular protease production by random mutagenesis of Aspergillus sp. using HNO2 as chemical mutagen. Materials and methods: Point inoculation of fungus was done in potato dextrose agar (PDA) plates for its macroscopic examination whereas lactophenol cotton blue staining of purified fungal colony was prepared for its microscopic observations. For chemical mutagenesis, spores of Aspergillus sp. were incubated with nitrous acid for different time durations thereafter protease activity was determined for screening of potent mutant strain. Results: Potent proteolytic soil fungal isolate was recognized as Aspergillus sp. based on its morphological characters observed directly from PDA plate culture and microscopic characters observed under compound microscope. Among the exposure time, mutagenic strain of Aspergillus sp. obtained after 90 min exposure with nitrous acid exhibited high level of protease activity (43.15 ± 0.40 U/ml) in submerged fermentation (SmF) which was 116% higher than wild strain (19.90 ± 0.85 U/ml). Conclusion: Fungal isolate was recognized as Aspergillus sp. by classical method of identification. Thereafter, protease activity was successfully increased up to 116% by chemical mutagenesis of Aspergillus sp. using nitrous acid as mutagen.
Keywords: Proteases, chemical mutagenesis, nitrous acid, Aspergillus sp., microscopic