No abstract

The extraction of feruloylated arabinoxylan (AX) from wheat bran was optimized in terms of the pretreatments prior to subcritical water extraction and then validated at the pilot scale. Destarching of wheat bran was critical to improve the yields and purity of the extracted AX. Time evolution profiles from sequential extractions revealed differences in the extractability of different polysaccharides, whereby β-d-glucans were first extracted followed by AX. At longer extraction times, the AX population was more substituted and more uniform in terms of molar mass distribution. Validation of the process at pilot scale (with a scaling factor of 33) resulted in AXs with similar molecular characteristics as in the laboratory scale. Both solid to liquid ratio and extraction time were essential in improving the yields. Our study demonstrated scalability of the process, opening opportunities for the further development of multifunctional food and material products from the extracted AXs.

Itaconic acid (IA) is a dicarboxylic acid included in the US Department of Energy's (DOE) 2004 list of the most promising chemical platforms derived from sugars. IA is produced industrially using liquid-state fermentation (LSF) by Aspergillus terreus with glucose as the carbon source. To utilize IA production in renewable resource-based biorefinery, the present study investigated the use of lignocellulosic biomass as a carbon source for LSF. We also investigated the production of fumaric acid (FA), which is also on the DOE's list. FA is a primary metabolite, whereas IA is a secondary metabolite and requires the enzyme cis-aconitate decarboxylase for its production. Two lignocellulosic biomasses (wheat bran and corn cobs) were tested for fungal fermentation. Liquid hydrolysates obtained after acid or enzymatic treatment were used in LSF. We show that each treatment resulted in different concentrations of sugars, metals, or inhibitors. Furthermore, different acid yields (IA and FA) were obtained depending on which of the four Aspergillus strains tested were employed. The maximum FA yield was obtained when A. terreus was used for LSF of corn cob hydrolysate (1.9% total glucose); whereas an IA yield of 0.14% was obtained by LSF of corn cob hydrolysates by A. oryzae.