Corn stover hydrolysate, a lignocellulosic feedstock for polyhydroxyalkanoate biosynthesis: property manipulation using a co-feed strategy with levulinic acid

Authors: Ashby, Richard - Rick; Solaiman, Daniel; Strahan, Gary

Submitted to: American Oil Chemists' Society Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 1/5/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Lignocellulosic feedstocks are interesting materials for bio-based product synthesis because of their availability and cheap cost. Our laboratory utilized corn stover hydrolysate (CSH) as a base feedstock for bacterially-derived polyhydroxyalkanoate biopolymer synthesis. Burkholderia sacchari DSM 17165 demonstrated an ability to utilize all of the available sugars present in the hydrolysate including glucose, xylose, galactose, and arabinose to produce poly (3-hydroxybutyrate) (PHB) in yields of approximately 2 g/L and productivities greater than 40% of the dry cell weight. In contrast, Azohydromonas lata DSM 1122 only used the glucose fraction of the hydrolysate but maintained comparable yields and productivities. Using varying ratios of levulinic acid as a co-feed allowed the production of copolymers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P3HB-3HV; B. sacchari) or poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxyvalerate) (P3HB-3HV-4HV; A. lata) with varying monomer ratios ranging from 0 to 25 mol% 3HV in B. sacchari and 0 mol% 3HB to 12 mol% 3HV to 8 mol% 4HB in A. lata as determined by 1H-NMR. The number-average molecular weights (Mn) of the polymers produced by A. lata were 63% smaller than those produced by B. sacchari with comparable polydispersities (weight-average molecular weight; Mw/Mn). These physical differences provided unique polymers with controllable mechanical properties.