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

Abstract

Heavy metal resistant bacteria are widespread in nature and their application in decontamination of polluted ecosystems is promising. In this study, ability of endophytic bacteria isolated from Psidium guajava (Guava) and Mangifera indica (Mango) for heavy metal resistance was assessed. Leaves samples form the two plants were collected and processed according to the standard laboratory practices. Heavy metals were analyzed using Atomic absorption spectrophotometer. Endophytic bacteria were isolated and identified using morphological and biochemical characteristics; heavy metal resistance was determined by plate dilution method. Heavy metal analysis revealed that the leaves samples contained considerable quantities of Manganese (Mn), Lead (Pb) and Cadmium (Cd) ranging from 1.21±1.6 mg/Kg (for Cd in Guava leaves) to 116.58±1.3 mg/Kg (for Mn in Mango leaves). A total of six bacterial species were isolated from both of the plants leaves (3 each). Guava endophytes were identified as Streptococcus sp, Staphylococcus albus and Staphylococcus seiuri whereas Staphylococcus aureus, Staphylococcus xylulose and Staphylococcus intermedius were from Mango leaves. The identified isolates were tested for ability to resist heavy metals in-vitro and were capable of showing different patterns of resistance to MnCl2, PbCl2 and CdCl2. All the endophytes were highly resistant to PbCl2 followed by MnCl2 but susceptible to CdCl2. The ability of plants and bacterial endophytes understudy to tolerate or resist heavy metals is a good indication of their phytoremediation potentials and thus, should be harnessed.

Assessment of resistance and biosorption ability of Lactobacillus paracasei to remove lead and cadmium from aqueous solution

“…It is well recognized that either human dependence on natural resources or worldwide industrial development has caused the water system exposure to the consecutive discharge of organic and inorganic pollutants (Lin et al, 2019;Saini et al, 2020). Heavy metals as one of the main environmental challenges have received much more attention over the decades because of their long-term persistence and toxicity in the low concentration, bioaccumulation potential, and neurotoxic and carcinogenic effects (Rahman et al, 2019;Riskuwa-Shehu et al, 2019). The release of heavy metals into the environment can threaten human survival and the life span of animals through the transfer of these contaminants into the food chain as a result of heavy metal solubility in water (Ahmed et al, 2018;Baltas et al, 2020).…”