Isolation and Characterization of Bacteria that Produce Polyhydroxybutyrate Depolymerases

Abstract

Isolation of environmental bacterial strains with diverse metabolic properties such as antibiotic production, sulfide oxidation, and the ability to use different nutrient sources is a common undergraduate lab experience. This article describes a useful protocol for the detection and isolation of bacteria that can degrade the common carbon storage biopolymer poly (3-hydroxybutyrate) (PHB). The procedure utilizes a low nutrient media supplemented with insoluble PHB that allows for the easy, visible detection of strains that produce extracellular PHB degrading enzymes. This method can be used to determine the percent of culturable bacteria from various environments that can degrade PHB. Further, PHB degrading exoenzyme activity can be monitored from pure cultures by: (1) Growing cells in broth, (2) inducing with PHB, and (3) measuring activity of supernatant with a UV/Vis spectrophotometer. The enzymatic breakdown of PHB presents an opportunity to expose students to the concept of using biodegradable plastics as a solution to the global plastic waste problem.