Hiệu quả phân hủy hoạt chất thuốc trừ sâu propoxur trong đất của dòng vi khuẩn Paracoccus sp. P23-7 cố định trong bã cà phê

Abstract

The main objective of this study was to evaluate the efficacy of spent coffee grounds as carrier material to immobilize propoxur degrading bacteria strain, Paracoccus sp. P23-7 on degradation of propoxur in soil collected from shallot cultivation soil in Vinh Chau, Soc Trang province. Wood biochar and spent coffee grounds were used as two carrier materials to compare their function on immobilization and degradation capacity of propoxur in soil. Cow manure, azolla, milled eggshell and domestic charcoal were materials used to amend into the soil. Soil bacterial and fungal numbers and remained concentration of propoxur in soil were determined at day 0, 1, 3, 5, 7 and 11 of the experiment. The results showed that degradation of propoxur in soil by Paracoccus sp. P23-7 was more effective when this bacterial strain was immobilized in spent coffee grounds than in wooden biochar. The treatment amended with 1% milled eggshells (w/w) or 1% biomixture including cow manure, azolla, milled eggshell and domestic charcoal had higher propoxur degradation than other treatments. The results allowed us to conclude that spent coffee grounds could be reutilized as carrier material to immobilize Paracoccus sp. P23-7 strain to enhance the degradation of propoxur in soil and degradation result would be even much better if the soil was amended with either 1% milled eggshells or 1% biomixture. These materials can be used as soil amender or soil conditioner to accelerate the efficacy of bioremediation technology in cleaning up the contaminated soil.