Increase in biodegradation of paclobutrazol in soils

Background Paclobutrazol is a regulator of vegetal growth that remains active in the soil and can affect the growth and the development of subsequent cultures. Experiments in two soils (A and B) with and without addition of inoculum or mineral medium were performed to investigate the biodegradation of paclobutrazol. The inoculum contained a mixed culture of three strains of bacteria isolated by enrichment and characterized as Pseudomonas. Flasks were incubated at ambient temperature, during 40 days. Paclobutrazol was quantified by high performance liquid chromatography. Addition of inoculum and mineral medium increased the biodegradation in both soils. The biodegradation ranged between 8 and 95%. Higher biodegradation was obtained with addition of mineral medium, independently of soil utilized.