Related Experiment Video
Updated: Sep 29, 2025

Characterization of a Pathogenic Escherichia coli Strain Derived from Oreochromis spp. Farms Using Whole-Genome Sequencing
Published on: December 23, 2022
Characterization and diversity of native Azotobacter spp. isolated from semi-arid agroecosystems of Eastern Kenya
Priscillah Wanjira Wakarera1, Patroba Ojola1, Ezekiel Mugendi Njeru1
1Department of Biochemistry, Microbiology and Biotechnology, Kenyatta University, PO Box 43844-00100, Nairobi, Kenya.
Abstract:
Declining food production in African agroecosystems is attributable to changes in weather patterns, soil infertility and limited farming inputs. The exploitation of plant growth-promoting soil microbes could remedy these problems. Such microbes include Azotobacter; free-living, nitrogen-fixing bacteria, which confer stress tolerance, avail phytohormones and aid in soil bioremediation. Here, we aimed to isolate, characterize and determine the biodiversity of native Azotobacter isolates from soils in semi-arid Eastern Kenya. Isolation was conducted on nitrogen-free Ashby's agar and the morphological, biochemical and molecular attributes evaluated. The isolates were sequenced using DNA amplicons of 27F and 1492R primers of the 16S rRNA gene loci. The Basic Local Alignment Search Tool (BLASTn) analysis of their sequences revealed the presence of three main Azotobacter species viz., Azotobacter vinelandii, Azotobacter salinestris and Azotobacter tropicalis. Kitui County recorded the highest number of recovered Azotobacter isolates (45.4%) and lowest diversity index (0.8761). Tharaka Nithi County showed the lowest occurrence (26.36%) with a diversity index of (1.057). The diversity was influenced by the soil pH, texture and total organic content. This study reports for the first time a wide diversity of Azotobacter species from a semi-arid agroecosystem in Kenya with potential for utilization as low-cost, free-living nitrogen-fixing bioinoculant.
Related Concept Videos
Diversity of Archaea I
Diversity of Archaea II
The Roles of Bacteria and Fungi in Plant Nutrition
Bacterial Phylum Bacteroidota
Diversity of Archaea IV
Diversity of Archaea III

