Biocorrosion Inhibition of Buried Carbon Steel Using Chromolaena Odorata Extracts.

Abstract:

Microbiologically influenced corrosion (MIC) threatens buried carbon-steel infrastructure, particularly in petroleum-impacted soils where sulfate-reducing and biofilm-forming bacteria accelerate metal deterioration. Although synthetic biocides are commonly applied, environmental toxicity, microbial resistance, and operational concerns necessitate green alternatives. The potential of Chromolaena odorata, a phytochemically rich plant, remains largely unexplored in microbial corrosion mitigation. This study evaluated the inhibitory effects of aqueous C. odorata extract on microbial communities and corrosion of carbon steel in produced-water-enriched soil. The research aimed to determine the extract’s biocorrosion-inhibitory capacity using gravimetric and metagenomic approaches. Soil samples were enriched with 200 mL produced water per 1 kg soil, and carbon-steel coupons (5 × 2 × 0.1 cm, 50g initial weight) were buried for 28 days. Microbial profiles were characterized via 16S rRNA sequencing, and corrosion rates assessed by weight loss. Results indicated that the extract substantially suppressed corrosion-associated bacteria, including Pseudomonas (15.32% → 0%), Salinispora (6.75% →1.3%), Comamonas (8.45% → 1.2%), Clostridium (4.76% → 0.8%), and Pseudomonas balearica (1.91% → 0%). Corrosion rate decreased from 30.35mm/year in untreated coupons to 4.92 and 4.33 mm/year in treated coupons for ethanolic and aqueous extracts of C. odorata respectively, representing 83.89% and 85.97% inhibition efficiency. While unclassified taxa remained high (~32%), treated soils exhibited a less corrosive microbiome structure. In conclusion, C. odorata extract selectively inhibits key MIC organisms, significantly reducing biocorrosion in buried steel. Further optimization through phytochemical fractionation, dose refinement (100 mg/mL), and field validation is recommended. Adoption of this green inhibitor offers sustainable corrosion management, reduces reliance on toxic biocides, and supports eco-friendly pipeline maintenance in petroleum and water-distribution systems.