title: Poly-beta-hydroxybutyrate production by fast-growing rhizobia cultivated in sludge and in industrial wastewater.
abstract: In our study, the potential of producing polyhydroxybutyrate (PHB) by cultivating fast-growing rhizobia (Sinorhizobium meliloti, Rhizobium leguminosarum bv. viciae, R. leguminosarum bv. phaseoli and R. leguminosarum bv. trifolii) in sludge and in industrial wastewater was evaluated. Results confirmed the possibility of using sludge as media for rhizobial growth. During growth, substantial quantity of PHB was accumulated and yields varied depending on the media and rhizobial species. Growing in sludge, PHB production did not exceed 3.7% w/w for all strains at the end of experiment (after 72 h). During the growth of S. meliloti, PHB yield varied and the maximum value reached 7.27% w/w after 60 h, with 1% Total Suspend Solid (TSS) sludge. Alkaline sludge pre-treatment affects rhizobial growth but did not improve the PHB accumulation. While growing S. meliloti in industrial wastewater, the PHB yields varied and the highest value was obtained with slaughterhouse wastewater (10.7% w/w) after 35 h of growth. Therefore, this work shows the potential of exploiting PHB production by rhizobia growing in wastewater or sludge which could be applied to bioplastic industry, and confirms the potential of these recyclable wastes for high production of rhizobial cells useable for legumes inoculants production. This study provides an environmentally sound way of sludge and wastewater management and use in diverse biotechnological applications.
authors.affiliation: Institut National des Sciences et Technologies de la Mer-Sfax, Sfax, Tunisia.
authors.forename: Faouzi
authors.initials: F
authors.lastname: Ben Rebah
authors.forename: Danielle
authors.initials: D
authors.lastname: Prévost
authors.forename: Rajeshwar Dayal
authors.initials: RD
authors.lastname: Tyagi
authors.forename: Lassaad
authors.initials: L
authors.lastname: Belbahri
mesh_terms: D006863:Hydrogen-Ion Concentration; D006885:Hydroxybutyrates / Q000378:metabolism*; D007220:Industrial Waste; D011091:Polyesters / Q000378:metabolism*; D012231:Rhizobium / Q000254:growth & development* / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D016962:Sinorhizobium meliloti / Q000254:growth & development* / Q000378:metabolism*; D013997:Time Factors; D000094122:Polyhydroxybutyrates
chemical_list: D006885:Hydroxybutyrates; D007220:Industrial Waste; D011091:Polyesters; D012722:Sewage; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates