Screening and isolation of protease-producing bacteria from wastewater samples in Obafemi Awolowo University (OAU) Campus, Ile-Ife, Nigeria
Authors: Qudus Arogundade Femi , Abiodun Lawal Ridwan 
Published: July 2023

Background

Wastewater samples possess substantial potential as a valuable resource for the isolation of bacteria with the capacity to produce protease enzymes. Gaining insights into the proteolytic capabilities of these bacteria holds considerable significance for a wide range of industrial applications. Enhancing our understanding of the microbial diversity and protease production potential within wastewater can pave the way for the creation of customized enzymatic solutions tailored specifically for industrial needs.

Purpose

The purpose of this study was to isolate and identify protease-producing bacteria from wastewater samples collected at Obafemi Awolowo University Campus in Nigeria. The study involved isolating bacteria from the wastewater, identifying them, evaluating their growth on protease-supporting agar, determining their proteolytic activities, and screening bacterial colonies for protease production using skim milk agar medium.

Methods

Wastewater samples were aseptically collected from various locations within Obafemi Awolowo University Campus, located in Ile-Ife, Osun State, Nigeria. Bacterial isolation from the wastewater was performed using the serial dilution technique. The samples were progressively diluted and plated onto nutrient agar media for bacterial growth. Skim milk agar media was specifically used to isolate protease-producing bacteria. Following the isolation, screening was conducted to identify potential protease-producing bacteria. Zonal inhibition methods were employed using skim milk agar media during the screening process. The objective was to select bacterial isolates that exhibited clear zones around their colonies, indicating protease activity. To identify the potential protease-producing bacteria, morphological and biochemical tests were conducted. These tests included observations of colonial morphology, cellular morphology, and biochemical characteristics. The Bergey’s Manual was used as a reliable reference for taxonomic classification during the identification process.

Results

Among the ten bacterial colonies obtained from the wastewater samples, eight exhibited clear zones, indicating protease activity. Morphological and biochemical tests identified the protease-producing bacteria asBacillus spp. andPseudomonas spp. Further characterization revealed that theBacillus licheniformisisolate from Water Sample D1 (WSD1) displayed the highest protease activity.Bacillus subtilisisolates also showed significant protease production, whilePseudomonas spp. exhibited lower protease production.

Conclusions

Wastewater samples from the OAU Campus yielded protease-producing bacteria, withBacillus licheniformisshowing the highest activity. The findings highlight the industrial potential of the isolatedBacillus licheniformisstrain and emphasize the significance of utilizing wastewater as a source for obtaining bacteria with protease production capabilities. Further studies on individual strains within theBacillusandPseudomonasgenera may lead to the discovery of strains with enhanced protease production, enabling tailored enzymatic solutions for various industrial sectors. Overall, this study contributes to our understanding of protease-producing microorganisms.