Abstract
Cyanobacteria synthesize a variety of chemically-different, high-value biopolymers such as glycogen (polyglucose), poly-β-hydroxybutyrate (PHB), cyanophycin (polyamide of arginine and aspartic acid) and volutin (polyphosphate) under excess conditions. Especially under unbalanced C to N ratios, glycogen and in some cyanobacterial genera also PHB are massively accumulated in the progression of the general nitrogen stress response. Several different technologies have been established for in situ and in vitro PHB analysis from different microbial sources. In this protocol, a rapid and reliable spectrophotometric method is described for PHB quantification in the cyanobacterium Synechocystis sp. PCC 6803 upon nitrogen deprivation as described in ( Damrow et al., 2016 ).