Potential Fungal-bacterial Biofilm for Bioremediation Polluted Soils of Chromium and Its Impact on Maize Growth

Recently, biofilm has emerged as a notable agent in bioremediation. The present study was conducted to determine the potential of microbes described in forming fungal-bacterial biofilm (FBB) as a bioremediation agent for chromium-contaminated soil. Parameters observed include total chromium concentration in soil, Zea mays growth, total chromium concentration in tissue, and its effects on microbial populations. The study commenced with biofilm formation assays and pot experiments in a greenhouse using combinations of chemical fertilizer (CF) on Zea mays. This research employed a Completely Randomized Design (CRD) with five treatments and four replications: A (100% CF), B (75% CF + 25% FBB), C (50% CF + 50% FBB), D (25% CF + 75% FBB), E (100% FBB). The results indicate that all treatments could reduce total chromium concentration below the threshold limit (2.5 mg kg-1), the lowest chromium concentration found in treatments D and E at 1.25 mg kg-1. FBB alone or in combination with CF did not enhance Zea mays growth. Treatment E exhibited plant height, crown dry weight, and root dry weight sequentially 20.31%, 84.10%, and 76.15% lower than treatment A. FBB could increase chromium accumulation in plants, with treatment E having the highest chromium concentration in crown and roots, at 15.47 µg g-1 and 15.59 µg g-1. Application of 100% FBB increased soil bacterial population by 44.02% compared to treatment A. In conclusion, the microorganisms identified can form FBB and serve as bioremediation agents by enhancing heavy metal accumulation in plants (phytoextraction).