Bioprospecting Soil Bacteria for Protease Production Using Agro-Waste: Toward Sustainable Detergent Formulations
Agro-waste valorization; Bacillus aerius; Enzyme-based stain remover; Protease; Soil bacteria
Purpose: Microbial proteases, particularly from soil-dwelling Bacillus species, are preferred over plant- and animal-derived enzymes due to their high yield, stability, and cost-effectiveness for large-scale production in industries. This study aimed to isolate and characterize potent protease-producing bacteria from soil and explore their application in developing a sustainable, bio-based stain remover. The formulation incorporates waste (citrus fruit peel and flower), promoting the valorization of agro-waste as part of a sustainable waste management strategy. Methods and Results: Soil samples collected from market waste disposal sites in Madurai, Tamil Nadu, yielded eight distinct bacterial isolates, among which strain S-5 showed the highest proteolytic activity on skimmed milk agar. Molecular identification confirmed the isolate as Bacillus aerius based on 16S rRNA sequencing.The crude enzyme extract obtained after 48h of incubation exhibited maximum proteolytic activity at pH 11, with an activity of 0.928U/mL. This confirms that enzyme production improves at higher pH levels. A biodegradable stain remover was prepared by combining the crude protease extract with citrus peel extract in water and ethanol formulations. The prepared formulation effectively removed oil, paint, and dye stains from cotton cloth within 20min of treatment without mechanical rubbing, whereas control samples showed minimal stain removal. Ethanol-based formulations demonstrated higher cleaning efficiency compared to water-based extracts, showing extensive stain removal in all replicates, while control treatments showed only minor or minimal removal. Conclusion: The integration of microbial proteases from soil-derived bacteria with agro-waste components produced an eco-friendly stain remover, offering a sustainable alternative to chemical detergents and promoting waste valorization in circular economy-based green product development. The Author(s), under exclusive licence to Springer Nature B.V. 2026.
Shree, J. G. Bharani; Madhavan, Aravind; Arun, K.B.
Springer Science and Business Media B.V.
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https://doi.org/10.1007/s12649-026-03646-4 https://www.scopus.com/pages/publications/105038920550?origin=resultslist
Shree J.G.B., Department of Life Sciences, CHRIST (Deemed to be University), Karnataka, Bangalore, 560029, India; Madhavan A., School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri Campus, Kerala, Kollam, 690525, India; Arun K.B., Department of Life Sciences, CHRIST (Deemed to be University), Karnataka, Bangalore, 560029, India