IPS Interdisciplinary Journal of Biological Sciences

Kinetics, Zymographic Analysis, and Industrial Evaluation of Alkaline Protease from Bacillus tropicus Isolated from Environmental Water Samples

B. O. Uba — 2026-05-08

This study investigated the isolation, molecular identification, and biotechnological potential of alkaline protease-producing bacteria from fish pond (FW) and poultry farm (PW) water samples. Serial dilutions 10⁻² and 10⁻³ were cultured on skim milk agar at 37 °C and pH 9 for 72 h to screen for proteolytic activity. Among the isolates, PW10⁻²A2 exhibited the highest protease activity with a zone of hydrolysis (ZOH) of 13 mm, compared to PW10⁻²A1 (4 mm) and PW10⁻²B2 (2 mm), despite the latter having >300 colonies. Molecular identification via 16S rRNA sequencing revealed 99.84% homology with Bacillus tropicus (GenBank accession MW971701.1). Zymogram analysis indicated two protease isoforms with molecular weights ranging between 36 and 116 kDa. Batch fermentation studies showed peak protease activity (142.02 U/mL) at 96 h, with a productivity of 1.48 U/h and specific growth rate of 0.0303 h⁻¹. Functional assays demonstrated complete blood stain removal when the enzyme was combined with detergent, outperforming detergent alone. Additionally, the enzyme exhibited efficient dehairing capability, with treated cow skin showing complete hair removal within 24 h compared to control. These findings highlight Bacillus tropicus PW10⁻²A2 as a promising candidate for industrial applications in detergent formulation and leather processing.

Molecular Identification, Phylogenetic Analysis, and Antibiotic Susceptibility Profiles of Bacteria Isolated from Borehole Water across Seasonal Variations

P. AN. Oghonim — 2026-04-14

Groundwater serves as a major source of potable water in many developing regions; however, its microbiological quality remains a public health concern. This study evaluated the bacterial diversity, seasonal variation, molecular identification, phylogenetic relationships, and antibiotic susceptibility profiles of bacteria isolated from borehole water sources. Total bacterial counts were determined for both rainy and dry seasons, revealing values ranging from 3.65–3.92 Log CFU/mL and 3.54–3.83 Log CFU/mL, respectively, with slightly higher counts observed during the rainy season. Bacterial isolates were identified using 16S rRNA gene sequencing and analyzed through BLASTn, which confirmed high similarity (97.88 – 99.86 %) with known species including Escherichia coli, Klebsiella aerogenes, Salmonella enterica, Proteus mirabilis, Pseudomonas aeruginosa, and Pseudomonas fluorescens. Phylogenetic analysis using the Neighbor-Joining method revealed clear clustering of isolates with reference strains, supported by high bootstrap values. Antibiotic susceptibility testing showed that most isolates were sensitive to fluoroquinolones, with ciprofloxacin demonstrating the highest efficacy. The findings highlight the presence of potentially pathogenic bacteria in borehole water and underscore the importance of continuous monitoring and appropriate water treatment strategies to safeguard public health.

Insect-Derived Spinigerin as an Imipenem Adjuvant: Combinatorial Activity against Clinical MDR Klebsiella pneumoniae Isolates

V. E. Ike — 2026-05-17

Carbapenem-resistant Klebsiella pneumoniae (CRKP) has emerged as a global health threat, rendering imipenem and other last-line antibiotics increasingly ineffective.. While antimicrobial peptides from insects have shown promise, the synergistic potential of termite-derived spinigerin with imipenem against clinical MDR K. pneumoniae isolates remains largely unexplored. This study investigated the combinatorial activity of spinigerin and imipenem against clinical MDR K. pneumoniae isolates. Three molecularly identified K. pneumoniae strains (KPA2, KPK6, KPDD) were isolated from urine samples. Minimum inhibitory concentrations (MICs) of spinigerin and imipenem, alone and in combination at nine ratios (9:1 to 1:9), were determined using broth microdilution. Spinigerin alone exhibited MICs of 0.25–0.5, while imipenem alone showed uniform MICs of 0.125. Combination therapy produced ratio-dependent MIC reductions, with maximal potentiation at 3:7 and 2:8 ratios (spinigerin:imipenem). KPK6 MIC decreased from 0.25 to 0.008 (31.3-fold reduction), KPA2 from 0.5 to 0.063 (7.9-fold), and KPDD from 0.5 to 0.125 (4-fold). One-way ANOVA confirmed significant MIC reductions across combination ratios for all isolates (F = 18.6–26.3, df = 10, p < 0.001). Post-hoc analysis revealed that ratios 5:5 to 2:8 produced significantly lower MICs than spinigerin alone (p < 0.01), whereas ratios 9:1 to 7:3 did not (p > 0.05). Spinigerin potentiates imipenem activity against MDR K. pneumoniae in a ratio-dependent manner, significantly reducing effective MICs.. This study provides the first evidence of spinigerin-imipenem synergy against clinical urinary isolates of K. pneumoniae, demonstrating that optimized peptide-antibiotic ratios can resensitize carbapenem-resistant strains.

The Impact of Fermented Mango Peel on Body Weight and Lymphocyte Counts

M. N. Okeke — 2026-04-27

The disposal of mango peel poses a significant agro-waste challenge, as peels account for 35–60% of total fruit mass during industrial processing, while the poultry industry seeks sustainable, antibiotic-free growth promoters. The specific impact of Lactobacillus-fermented mango peel on physiological parameters remains underexplored. This study investigated the effects of a Lactobacillus-fermented mango peel supplement on the body weight and blood lymphocyte levels of broiler chicks, addressing the dual challenge of agro-waste valorisation and sustainable poultry nutrition. Mango peel was fermented using an isolated bacterial strain designated 'P', which was rigorously characterised through cultural, biochemical, and molecular analyses and definitively identified as Lactobacillus acidophilus strain DSM20079 (100% 16S rRNA gene identity, Accession CP020620.1). In a seven-week feeding trial, chicks receiving the fermented supplement achieved a final mean body weight of 3.662 kg, significantly higher (24.0% increase) than the control group's 2.954 kg, demonstrating a potent growth-promoting effect. Concurrently, haematological analysis revealed a significant immunomodulatory outcome: the test group exhibited a mean total lymphocyte count of 276.46 ± 1.01, a value significantly elevated (81.7% increase above normal control) and comparable to chicks treated with the standard immunostimulant levamisole (273.19 ± 1.21). These results indicate that the fermented product not only enhances nutrient bioavailability and weight gain but also robustly stimulates systemic cellular immunity. The findings confirm that solid-state fermentation with a precisely identified probiotic strain can transform mango peel into a multifunctional feed additive that simultaneously improves zootechnical performance and immune status, offering a viable strategy for waste-to-resource conversion in sustainable animal production.