Isolation and Identification of Rhizobacteria with Biofertilizer Potential from Irrigated Rice Fields in Damaturu, Yobe State, Nigeria

Sheriff Wakil1, Haruna Yahaya Ismail2, Ibrahim Alkali Allamin2 and Adam Lawan Ngala3

1Department of Microbiology, Yobe State University, Damaturu, Nigeria
2Department of Microbiology, University of Maiduguri, Borno State, Nigeria
3Department of Soil Science, University of Maiduguri, Borno State, Nigeria

*Corresponding author’s Email: wakilsheriff028@gmail.com, doi.org/10.55639/607.special.002


ABSTRACT

The rhizosphere microbiome plays a key role in plant productivity and soil fertility, particularly in intensive systems such as irrigated rice cultivation. Although rice rhizosphere microbial communities have been widely studied, information from semi-arid regions of Nigeria remains limited. Biofertilizers offer an environmentally friendly alternative to chemical fertilizers, whose prolonged use negatively affects soil structure and fertility. This study examined the cultivable rhizobacterial community and physicochemical properties of irrigated rice fields in Damaturu, Yobe State, Nigeria. Ten rhizosphere soil samples (10 g each) were randomly collected at a depth of 0-15 cm. Physicochemical analyses were performed using standard methods, while microbiological assessment involved serial dilution (10⁻¹-10⁻⁷), pour plate culturing, and incubation at 30°C for 24-48 h. Isolates were characterized using Gram staining, biochemical tests, and plant growth-promoting trait assays. The soils were clay-loamy, slightly acidic to neutral (pH 6.1–7.1), and moderately fertile. Total bacterial counts ranged from 1.02 × 10¹² to 3.18 × 10¹² CFU/g, with the highest count recorded in sample S9. Seven rhizobacterial isolates were identified, dominated by Bacillus spp. (40%), followed by Pseudomonas spp. (20%) and Azotobacter spp. (10%). The predominance of Bacillus spp. reflects their spore-forming capacity, while the presence of all three genera indicates potential plant growth-promoting traits, including indole acetic acid production, ammonia production, and phosphate solubilization. These findings suggest that Bacillus sp. (S9) has potential as a biofertilizer for sustainable rice (Oryza sativa L. FARO) production and reduced reliance on chemical fertilizers in Damaturu, Yobe State.

Rhizosphere,
Biofertilizer,
PGPR,
Bacillus sp.

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