DOI: 10.1177/00368504261504868 ISSN: 0036-8504

Screening, isolation, and molecular analysis of bacteria producing protease enzymes from Eastern Hararghe and Dire Dawa, Ethiopia

Tadele Tekilu Megersa, Meseret Chimdessa Egigu, Duguma Dibbisa Itana
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Objective

This study aimed to screen, isolate, characterize, and perform molecular analysis of protease-producing bacteria from soil samples collected from Eastern Hararghe and Dire Dawa, Ethiopia, and to optimize selected fermentation conditions for alkaline protease production.

Methods

An experimental laboratory-based study was conducted using a completely randomized design (CRD) to evaluate protease production under different fermentation conditions. Fifteen bacterial isolates were initially screened for proteolytic activity using skim milk agar, and four isolates exhibiting prominent hydrolysis zones were selected for further investigation. The isolates were characterized using phenotypic methods and molecularly identified through 16S rRNA gene sequencing. Protease production was evaluated under varying carbon and nitrogen sources, substrate concentration, and pH conditions.

Results

The four selected isolates were identified as Alcaligenes faecalis , Pseudomonas spp., Bacillus spp., and Proteus mirabilis . All four isolates exhibited maximum alkaline protease activity at pH 9. The highest enzyme activity was recorded for Alcaligenes faecalis (123.61 ± 0.002 U/mL), followed by Bacillus spp. (105.01 ± 0.001 U/mL), for Pseudomonas spp., (104.71 ± 0.007) and Proteus mirabilis (101.61 ± 0.002 U/mL). These findings demonstrate the potential of the selected bacterial isolates to produce alkaline proteases under alkaline conditions.

Conclusions

The results indicate that soil microorganisms from Eastern Haraghe and Dire Dawa represent a promising source of alkaline protease-producing bacteria. Among the isolates investigated, A. faecalis demonstrated the highest protease activity and may be a promising candidate for further investigation. Additional studies on enzyme purification, biochemical characterization, stability, and production scale-up are recommended to assess the suitability of these isolates for industrial applications.

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