Isolation and Identification of Phosphate Solubilizing and Nitrogen-Fixing Bacteria from Lake Ol’Bolossat Sediments, Kenya

Abstract

Phosphate solubilizing and nitrogen-fixing bacteria have a vital role in improving soil fertility and reverting adversely affected soil properties. These bacteria could contribute towards sustainable agriculture with a focus on reducing excessive use of commercial fertilizers. This study aimed at investigating autochthonous populations of phosphate solubilizing and nitrogen-fixing bacteria from Lake Ol’Bolossat sediments. The total microbial counts ranged between 4.8 x 103 to 8.5 x 105 cfu/ml. A total of 50 bacteria were isolated, 34 were obtained from Pikovskaya’s agar medium while 16 were obtained from Norris Glucose Nitrogen free medium. Based on morphological and 16S rRNA gene analyses, the isolates were clustered under the genera Bacillus, Arthrobacter, Pseudomonas, Paenibacillus, Fictibacillus and Acinetobacter. Among potentially novel strains, four strains NFDA2, PKGBC1 (MT799539), PKGB5 and SCEC2 (MT799543) belonged to genus Bacillus, three strains NFGA1 (MT799529), NFGA4 and SCDB3 belonged to the genus Pseudomonas, two strains NFEB6 (MT799528) and NFDC5 belonged to the genus Paenibacillus, one strain PKHC3 (MT7995441) belonged to the genus Arthrobacter while one strain NFDC4, belonged to the genus Acinetobacter. Generally, the phosphate solubilizing bacteria were the most diverse and genera Bacillus, Fictibacillus and Pseudomonas were the most dominant, however, nitrogen-fixing bacteria were dominated by genera Arthrobacter and Pseudomonas.

Isolation and Characterization of Bacteria from Lakes Olbolosat and Oloiden, Kenya

“…Bacillus megaterium could be used as an industrial organism since it produces proteins and has been used in bioremediation. Proteins are commonly used in agriculture as plant promoting bacteria and in health sectors (Wafula and Murunga, 2020). Bacillus subtilis, B. cereus, B. pumilus, B. aryabhattai, Bacillus safesis subp safensis and B. simplex have been used as plant promoting bacteria to fix nitrogen, secrete plant hormones or antibiotics, solubilize phosphates, inhibit pathogenic microbes and modify insoluble iron to soluble iron (Chiboub et al, 2018).…”

“…It is separated from its west shore by a peninsula. The distance between Lake Naivasha and Lake Oloiden are about 200 m. Lake Olbolosat is a freshwater body and is about 43 Km 2 (Wafula and Murunga, 2020). The lake records pH of 7 and temp of 22°C.…”

“…Lake Olbolosat which means a marshy area in the Maasai language is a freshwater marine ecosystem and is endangered. The gradual drying up of this lake is probably due to human activities (Wafula and Murunga, 2020). Lake Oloiden, which means salty in the Maasai language, was also considered for its saline alkaline.…”

“…Culture-dependent technique studies from Lake Oloiden of the Kenyan Rift Valley revealed the presence of diverse populations of high G+C content belonging to the genus Artrobacter, Dietzia and Terrabacter (Duckworth et al, 1998). Bacteria of the genera, Pseudomonas Paenibacillus, Arthrobacter, Bacillus, Fictibacillus and Acinetobacter, have been isolated from L.Olbolosat (Wafula and Murunga, 2020). The current study is in line with the Kenyan government's big four priority areas within the framework of vision 2030 whereby the department of Regional Development Management supports the conservation of natural resources through sustainable utilization and conservation of river basins and large water bodies (Kiunjuri, 2017).The study is in line with African Commission priority areas of Agenda 2063 framework on the use of indigenous knowledge in Science and technology and innovation for sustainable development that acts with a sense of urgency on climate change and environment (AU, 2015).…”

Exploration of the rhizosphere microbiome of native plant Ceanothus velutinus – an excellent resource of plant growth-promoting bacteria

“…The bacterial isolates were streaked on the plates and incubated at 28 °C for three days or until a clear zone around the colony appeared. The appearance of a clear zone indicates a positive result for nitrogen fixation ( Wafula and Murunga, 2020 ; Gaete et al., 2022 ) ( Figure S2D ). Rhizobium leguminosarum C6 isolates used as a positive control.…”