Biostimulation Potential of Nypa fruticans Ash on Indegenous Heterotrophic Bacteria and Fungi for Enhanced Remediation of Hydrocarbon Polluted Soil at B. Dere, Rivers State, Nigeria

Abstract

This study was designed to evaluate the biostimulation potential of Nypa feuticans ash on the growth of indigenous heterotrophic bacteria and fungi for enhanced remediation of hydrocarbon polluted soil at B. Dere, Rivers State, Nigeria in an ex-situ experiment, using the completely randomized split plot experimental design. 2kg of oil polluted soils were treated with 10g, 20g, 30g, 40g, 50g and 60g of Nypa fruticans ash and monitored for biostimulation and growth of indigenous biodegrading heterotrophic bacteria (THBC) and fungi (THFC). The results of four months post residual and cumulative effect on treated soil showed optimum improvement of microbial load at 60g/2kg treatment of Nypa fruticans ash. Findings on THBC for post residual treatment soil ranged from 0.1×10⁵ to 8.0 ×10⁴ cfu/g, while the THFC ranged from 0.1×10⁴ to 3.0 ×10⁴ cfu/g. THBC for post cumulative treated soil ranged from 2.7 ×10⁵ to 9.0 ×10⁴ cfu/g, while THFC ranged from 0.2 × 10⁴ to 3.0 ×10⁴ cfu/g. Three bacteria genera isolated from the post treated soil ware Bacillus spp. (36.3%), Clostridium spp (33.4%) and staphylococcus spp. (30.3%), while two fungi genera namelyYeast spp. (58%) and Muccor spp. (42%) were isolated from the post treated soil. The high-count THB and THF recorded in both residual and cumulative treated soil compared to the oil polluted untreated soil is attributed to Nypa fruticans ash capacity to neutralize the toxic effects of the crude oil on the microbial population by rapid improvement of the soil physiochemical properties, favoring the growth of indigenous microorganisms in the soil. This study has shown that treatment of crude oil polluted soil with Nypa fruticans ash at 60g/2kg showed optimum improvement which enhanced the biostimulation and growth of indigenous petroleum degrading microorganism.