title: Characterization of poly-3-hydroxybutyrate (PHB) produced from Ralstonia eutropha using an alkali-pretreated biomass feedstock.
abstract: Alkaline pretreatment using NaOH, KOH, or NaOCl has been applied to various types of waste biomass to enhance enzymatic digestibility. Pretreatment (2% NaOH, 121 °C, 30 min) of rice paddy straw (PS) resulted in a maximum yield of 703 mg of reducing sugar per gram of PS with 84.19% hydrolysis yield after a two-step enzymatic hydrolysis process. Ralstonia eutropha ATCC 17699 was tested for its ability to synthesize poly-3-hydroxybutyrate (PHB) using PS hydrolysates as its sole carbon source. It is noteworthy that dry cell weight, polyhydroxyalkanoate (PHA) accumulation and PHB yield with the use of laboratory-grade sugars were similar to those achieved with PS-derived sugars. Under optimized conditions, we observed maximal PHA accumulation (75.45%) and PHB production (11.42 g/L) within 48 h of fermentation. After PHB recovery, the physicochemical properties of PHB were determined by various analytical techniques, showed the results were consistent with the characteristics of a standard polymer of PHB. Thus, the PS hydrolysate proved to be an excellent cheap carbon substrate for PHB production.
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seongbuk-gu, Seoul 136-713, South Korea.
authors.forename: Ganesh D
authors.initials: GD
authors.lastname: Saratale
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seongbuk-gu, Seoul 136-713, South Korea. Electronic address: mkoh@korea.ac.kr.
authors.forename: Min-Kyu
authors.initials: MK
authors.lastname: Oh
mesh_terms: D000468:Alkalies / Q000494:pharmacology*; D018533:Biomass; D050260:Carbohydrate Metabolism / Q000187:drug effects; D020118:Cupriavidus necator / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D006868:Hydrolysis; D006885:Hydroxybutyrates / Q000737:chemistry / Q000378:metabolism*; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*; D013059:Spectrum Analysis, Raman; D013818:Thermogravimetry; D000094122:Polyhydroxybutyrates
chemical_list: D000468:Alkalies; D006885:Hydroxybutyrates; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates
keywords: Alkaline pretreatment; Poly-3-hydroxybutyrate; Rice paddy straw