Survival of poly-3-hydroxybutyrate-producing bacteria in soil microcosms

Bacillus megaterium is a potential bioremediation and biocontrol agent. The accumulation of reserve polymers, such as poly-3-hydroxybutyrate (PHB), in creases survival of B. megaterium in water. We used wild-type strains of th is species and mutant strains deficient in PHB synthesis in soil microcosms for testing the hypothesis that differences in survival capabilities and s pore quality between strains is maintained in heterogeneous environments en riched with organic matter. No differences in survival between strains, nor a decrease in bacterial cell numbers were observed in sterile soil microco sms. In non-sterile soil, the total cell number (vegetative cells plus spor es) of the PHB wild-type strain was 3.5 times higher than that of the PHB-n egative mutant. We suggest that for predictive purposes, validation of surv ival in a variety of conditions is necessary.