Study of Biodegradable Polyesters from Algal Sources for Use in Future Textile Fiber Applications

摘要

Polyhydroxyalkanoates (PHAs) are a family of linear biodegradable thermoplastic polyesters that are synthesized in nature by bacterial fermentation. The formation is triggered by deficiency of nutrients and the excess supply of carbon sources. Inspite of high yield of PHAs via bacterial fermentation, it is not an economically viable route due to high costs incurred by expensive carbon sources and rich oxygen supply during bacterial fermentation. In order to reduce the cost of PHA, photoautotrophic production is thought to be a desired route. Cyanobacteria are one of the only prokaryotic species that naturally produces PHAs (under stress conditions) by photosynthesis and requires fewer resources for growth and biomass production. The current study describes the investigation of the mixotrophic biosynthesis of PHB (poly 3-hydroxy butyrate) in cyanobacteria (blue green algae) (Nostoc sp.) followed by extraction of the biosynthesized polymer using methanol-chloroform solvent extraction technique and characterization of the physicochemical properties. The results suggested that the Nostoc sp. culture is a viable candidate for production of PHB polymers. The PHB content of ～8.4% (w/w of dry cellular weight (dcw)) of Nostoc sp. cells in a 7- day incubation period proves its feasibility in producing the biopolymer in environmental stress conditions. The extracted polymers (in the fiber/yarn form) in the future are proposed to be used in various textile-related medical applications such as tissue scaffolds, sutures threads and surgical meshes.