Enhanced biodegradation of hexachlorocyclohexane (HCH) isomers by Sphingobium sp. strain D4 in the presence of root exudates or in co-culture with HCH-mobilizing strains

ANALIA ALVAREZ; RODRIGUEZ-GARRIDO BEATRIZ; CERDEIRA-PEREZ ANDREA; TOMÉ-PÉREZ ALBA; KIDD PETRA; PRIETO-FERNÁNDEZ ANGELES

JOURNAL OF HAZARDOUS MATERIALS.

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2022 vol. 433 p. 128764 - 128764

0304-3894

Lindane and other 1,2,3,4,5,6-hexachlorocyclohexane (HCH) isomers are persistent organic pollutants highly hydrophobic, which hampers both their availability and biodegradation. This work aimed i) to investigate the genes encoding enzymes that are essential for HCH degradation in the bacterium Sphingobium sp. strain D4 and ii) to analyse how biodegradation of HCHs may be enhanced by strain D4 in the presence of root exudates or in co-culture with HCH-mobilizing strains. Fragments of the same size and similar sequence to linA and linB genes were successfully amplified. Biodegradation of HCH isomers by strain D4 was enhanced in the presence of root exudates. Another two bacteria, were selected because of their ability to produce emulsifier compounds. Cell-free supernatants of both strains increased the mobility of the HCH isomers, particularly in soil with high organic matter (OM). Co-inoculation of the degrader strain D4 with either of the other strains stimulated dissipation of HCHs, especially in soil with low OM. In all soil slurries tested, the HCH content decreased by more than 95%. The combination of HCH-degrading and HCH-mobilizing strains can be considered a promising inoculum for future soil bioremediation studies using bioaugmentation techniques or in combination with plants in rhizodegradation assays.