Screening of Some Lactic Acid Bacteria and Bifidobacteria for Their Capability for Removing of Heavy Metals and Aflatoxin B1 From Contaminated Water

Abstract

This study assessed the capacity of five microrganisms oflactic acid bacteria (LAB), Lactobacillus johnsonii ATCC 3320, Lactobacillus salivarius TISTR 390, Lactobacillus paracasei TISTR 453, and Lactobacillus helveticus LH-BO2L) and probiotic bacteria (Bifidobacterium lactis strain Bb12)  and their combination to eliminate heavy metals (HM) like arsenic (As), lead (Pb), and cadmium (Cd) as well as mycotoxin aflatoxin B1 (AFB1) from contaminated water. Both single and mixed LAB and probiotic bacteria were used to test the biosorption parameters (pH, bacterial concentration, contact time, and temperature) of removal. The data showed that HM and AFB1 removal was influenced by the strain and that the process was very pH-dependent, with strong binding at a pH of about neutral. An increase in the bacterial content increased the binding of As, Pb, and Cd. Furthermore, increasing the contact time and treatment temperature improved the ability of LAB strains to eradicate HM. The effect of contact duration on Cd elimination was slightly different with freshly cultured cells. As the initial metal content increased, so did the perceptual elimination of Cd, Pb, and As. Bifidobacterium lactis strain Bb12, Lactobacillus johnsonii ATCC 3320, and the combination of the microbes were the most highly successful HM removers. It was determined that the system was sufficient for the HM concentrations being studied.By the end of the procedure, the HM concentration had reached the maximum permitted by WHO guidelines. These findings provide insights for selecting and optimizing the conditions to increase the capability of LAB for removing of heavy metals and aflatoxin B1 from contaminated water as primary basic biomethod for production of biofilter for purification of contaminated water.