Biosorption of heavy metal polluted soil using bacteria and fungi isolated from soil

Abstract

Heavy metals polluted soils have turned out to be a common environmental problem across the globe due to their toxic effects and accumulation through the food chain. Heavy metals have lethal effects on all forms of life. For instance, plants grown on heavy metal polluted soil show a reduction in growth and yields. A surge in anthropogenic activities and industrial operations has substantially increased the level of heavy metal pollution and release into the environment; hence, there is need to remediate these heavy metal pollutants. Biosorption is an efficient, economical, ecofriendly and convenient techniques of remediating heavy metal polluted soils. It is a widely accepted method that utilizes biomaterials such as natural biomass as biosorbents. The current study was based on the biosorption of copper, chromium, cadmium and nickel polluted soil using bacteria and fungi isolated from soil. Bacterial species isolated were Pseudomonas, Bacillus, Micrococcus, Escherichia, Streptococcus, Enterobacter and Staphylococcus while fungi isolated were Aspergillus niger, Penicillium notatum and Aspergillus flavus. The isolated bacteria were screened for potential to biosorb copper and chromium likewise fungi for cadmium and nickel. Biosorption rate was determined using atomic absorption spectrophotometry. Five milliliters each of a-day-old culture of the screened bacteria and fungi was inoculated into 45 ml of nutrient broth (bacteria) and potato dextrose broth (fungi) having concentrations of 5, 10, 15 and 20 ppm, respectively, of copper, chromium, cadmium and nickel. The conical flasks were incubated at a temperature of 37 °C and 28 °C ± 2 for bacteria and fungi, respectively, for a period of 35 days of inoculation. For the bacterial isolates, the highest biosorption rates of chromium (89.67%) and copper (90.89%) by Pseudomonas aeruginosa were observed at 20 ppm on day 21 and 15 ppm on day 14, respectively, while for the fungi isolates, P. notatum showed highest biosorption rate for cadmium at 10 ppm with 77.67%. Aspergillus niger showed highest biosorption rate for nickel with 81.07% after 28 days of incubation. The results of this study revealed the ability of Pseudomonas aeruginosa to biosorb copper and chromium and also A. niger and P. notatum to biosorb cadmium and nickel from the environment and can be developed for the biosorption of soils polluted with copper, chromium, cadmium and nickel.

Restoration of heavy metal‐contaminated soil and water through biosorbents: A review of current understanding and future challenges

“…Different genera of bacteria belonging to Bacillus , Pseudomonas , Micrococcus , Streptococcus , Staphylococcus , and Enterobacter have been successfully used as biosorbent for heavy metal in soil and water (Oyewole et al, 2019). Bacteria derived products like EPS (exopolysaccharides) are mainly acidic, containing hydroxyl, phosphoryl, sulfide, carboxyl, and amide groups and have the affinity to bind metals in soil (Bramhachari & Nagaraju, 2016).…”

“…Bioavailable fractions of heavy metals in the soil easily accumulate in flora and fauna, causing irreparable damage to the ecosystem. Although small quantities of metals like Co, Cu, Fe, Ni, and Zn are required for normal plant growth, higher concentrations reduce soil fertility and agricultural productivity (Oyewole et al, 2019). Some metals like As, Cr, Pb, Cd, Hg, and U are very toxic even at low concentrations.…”

“…Therefore, green, cheap, and sustainable approaches need to be explored for large‐scale application. The application of biosorbents for heavy metal sequestration from soil and water has been successfully demonstrated by various research groups (Ayangbenro & Babalola, 2017; Dhanarani et al, 2016; Oyewole et al, 2019). Biosorbents accumulate heavy metals through adsorption, complexation, precipitation, ion exchange processes, and physicochemical interactions between metal and functional groups (hydroxyl, carboxyl, amines, sulfides, ketones, aldehydes) present on the cell membranes (Dhanarani et al, 2016).…”

Heavy Metal Resistance by Endophytic Bacteria Isolated from Guava (Psidium Guajava) and Mango (Mangifera Indica) Leaves

“…Thus, some microbes may play a vital role in the biogeochemical cycling of toxic heavy metals and also in cleaning up metal contamination [21,22]. A lot of studies have explored the applicability of microorganisms in ameliorating heavy metal contamination and some were found to be exciting [23,26]. This led to the development of some biotechnological processes for remediation of polluted environments tagged as bioaccumulation and biosorption [26,27].…”

“…A lot of studies have explored the applicability of microorganisms in ameliorating heavy metal contamination and some were found to be exciting [23,26]. This led to the development of some biotechnological processes for remediation of polluted environments tagged as bioaccumulation and biosorption [26,27]. Bioaccumulation is a process that involves the uptake and removal of environmental pollutants (both organic and inorganic) by microorganisms.…”