Remarkable shift in structural and functional properties of an animal charcoalpolluted soil accentuated by inorganic nutrient amendment
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Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Genetic Engineering and Biotechnology
Abstract
Background: Soils polluted with animal charcoal from skin and hide cottage industries harbour extremely toxic and
carcinogenic hydrocarbon pollutants and thus require a bio-based eco-friendly strategy for their depuration. The
effects of carbon-free mineral medium (CFMM) amendment on hydrocarbon degradation and microbial community
structure and function in an animal charcoal-polluted soil was monitored for 6 weeks in field moist microcosms
consisting of CFMM-treated soil (FN4) and an untreated control (FN1). Hydrocarbon degradation was monitored
using gas chromatography-flame ionization detector (GC-FID), and changes in microbial community structure were
monitored using Kraken, while functional annotation of putative open reading frames (ORFs) was done using KEGG
KofamKOALA and NCBI’s conserved domain database (CDD).
Results: Gas chromatographic analysis of hydrocarbon fractions revealed the removal of 84.02% and 82.38%
aliphatic and 70.09% and 70.14% aromatic fractions in FN4 and FN1 microcosms in 42 days. Shotgun metagenomic
analysis of the two metagenomes revealed a remarkable shift in the microbial community structure. In the FN4
metagenome, 92.97% of the population belong to the phylum Firmicutes and its dominant representative genera
Anoxybacillus (64.58%), Bacillus (21.47%) and Solibacillus (2.39%). In untreated FN1 metagenome, the phyla
Proteobacteria (56.12%), Actinobacteria (23.79%) and Firmicutes (11.20%), and the genera Xanthobacter (9.73%),
Rhizobium (7.49%) and Corynebacterium (7.35%), were preponderant. Functional annotation of putative ORFs from
the two metagenomes revealed the detection of degradation genes for aromatic hydrocarbons, benzoate, xylene,
chlorocyclohexane/chlorobenzene, toluene and several others in FN1 metagenome. In the FN4 metagenome, only
seven hydrocarbon degradation genes were detected.
Conclusion: This study revealed that though CFMM amendment slightly increases the rate of hydrocarbon
degradation, it negatively impacts the structural and functional properties of the animal charcoal-polluted soil. It
also revealed that intrinsic bioremediation of the polluted soil could be enhanced via addition of water and
aeration
Description
Staff Publication
Keywords
Animal charcoal-polluted soil,, Carbon-free mineral medium,, Hydrocarbon degradation,, Illumina shotgun sequencing,, Microbial Community Structure,, Soil microcosm