Glycerine and levulinic acid: renewable co-substrates for the fermentative synthesis of short-chain poly(hydroxyalkanoate) biopolymers.
Glycerine (a biodiesel co-product) and levulinic acid (a pulp and paper co-product) were used as co-substrates for the fermentative synthesis of short-chain polyhydroxyalkanoate (sc-PHA) biopolymers with tunable monomer and molecular weight characteristics. Pseudomonas oleovorans NRRL B-14682 utilized glycerine alone to produce poly(3-hydroxybutyrate) (PHB). When levulinic acid was added to the media at shake-flask scale in concentrations ≤0.6 wt.%, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB/V) copolymers were produced with 3-HV contents ranging from 37 to 97 mol%; a glycerine:levulinic acid ratio of 0.2%:0.8% (w/v) resulted in poly(3-hydroxyvalerate) (PHV). Ten-liter batch fermentations using glycerine:levulinic acid ratios of 1%:0, 0.75%:0.25%, 0.5%:0.5% and 0.25%:0.75% (w/v) resulted in PHB, P(73%-3HB-co-27%-3HV), P(30%-3HB-co-70%-3HV) and PHV with increasing number average molecular weights (×10(3) g/mol) of 328, 511, 728 and 1330, respectively, owing to glycerine-based chain termination. These results provide a novel means by which glycerine and levulinic acid can be used collectively to produce an array of distinct sc-PHA biopolymers.
Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA. Rick.Ashby@ars.usda.gov
Richard D
RD
Ashby
Daniel K Y
DK
Solaiman
Gary D
GD
Strahan
Chengjun
C
Zhu
Ryan C
RC
Tappel
Christopher T
CT
Nomura
D061249:Batch Cell Culture Techniques; D018533:Biomass; D001704:Biopolymers / Q000096:biosynthesis*; D019149:Bioreactors / Q000382:microbiology; D002152:Calorimetry, Differential Scanning; D005285:Fermentation / Q000502:physiology*; D005990:Glycerol / Q000378:metabolism*; D007982:Levulinic Acids / Q000378:metabolism*; D008970:Molecular Weight; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*; D011549:Pseudomonas / Q000378:metabolism; D059027:Recycling; D059205:Renewable Energy; D013718:Tensile Strength
D001704:Biopolymers; D007982:Levulinic Acids; D054813:Polyhydroxyalkanoates; D005990:Glycerol; C032246:levulinic acid