Polyhydroxybutyrate (PHB): Microbial Production, Properties, Extraction and Biomedical Applications

Abstract

Polyhydroxybutyrate (PHB), a member of the polyhydroxyalkanoate (PHA) family, is a biodegradable and biocompatible thermoplastic polymer synthesized by a diverse range of bacteria under nutrient-limiting conditions. This chapter explores the structural characteristics, physicochemical properties, biosynthesis pathways, physiological roles, and microbial sources of PHB. The ability of both Gram-positive and Gram-negative bacteria to produce PHB from various carbon sources makes it a promising alternative to petrochemical plastics. The metabolic pathways involved in PHB synthesis and degradation, including key enzymes such as PhbA, PhbB, and PhbC are discussed. Furthermore, the chapter examines the multifunctional role of PHB in microbial stress tolerance and its potential in biomedicine, particularly in tissue engineering and drug delivery. Different methods for PHB extraction, including solvent and surfactantbased techniques, are evaluated for their efficiency and environmental impact. With its wide range of applications, PHB stands at the forefront of sustainable materials research and development.