Acetone–Butanol–Ethanol Production from Fermentation of Hot-Water-Extracted Hemicellulose Hydrolysate of Pulping Woods

Abstract

In the kraft pulping process, the hemicellulose portion of wood is usually discharged as a waste stream into the black liquor, representing a highly underutilized sugar source. In this study, the hemicellulose prehydrolysate is investigated as a liquid sugar source for production of acetone, butanol, and ethanol by ABE fermentation. For this purpose, hot-water treatment is applied to poplar (hardwood) and southern pine (softwood) for hemicellulose extraction. The acquired hemicellulose prehydrolysate was analyzed to contain, in addition to the carbohydrates in the form of oligosaccharides, various degradation compounds. The toxicity test with model compounds indicates phenolic compounds exert tremendous inhibition on the cell growth. Therefore, detoxification is required prior to fermentation. Adsorption with activated carbon is an effective detoxification method greatly reducing the phenolic content and alleviating the phenol-induced inhibition. Upon detoxification, simultaneous saccharification and fermentation (SSF) of concentrated poplar prehydrolysate with 43.3 g/L sugar produced a total of 10.8 g/L ABE giving a solvent yield of 0.25 g of solvent/g of sugar. Comparatively, SSF of concentrated southern pine prehydrolysate with 46.6 g/L sugar resulted in an ABE production of 13.2 g/L and productivity of 0.28 g of solvent/g of sugar. The details of hotwater-extraction conditions, the performance of detoxification, and the fermentation profiles are discussed. The technical feasibility of utilizing the hemicellulose prehydrolysate as feedstock for biobutanol production has proposed an example of the concept of an integrated biorefinery.

Hot Water Extraction Improves the Characteristics of Willow and Sugar Maple Biomass With Different Amount of Bark

“…HWE conducted for only 1 h, under approximately the same conditions, yields lower mass removal than what is found in this present study. Guan et al found mass removal of 15.7% when HWE is performed on debarked hybrid poplar for 1 h at 170 • C (Guan et al, 2018). HWE of sugar maple removed 14.2% of the initial weight, when operated at 160 • C for 1 h (Mittal et al, 2009a).…”

Cellulase production from kraft hardwood pulp by Trichoderma reesei rut C‐30

“…The integrated ‘biorefinery’ process to produce biofuels and chemicals as a supplementary unit in kraft paper mills is an intriguing possibility . Our previous research found that the production of various chemicals could be integrated into the kraft process, while still preserving the main products ‐ paper and pulp . However, the biggest bottleneck in this biorefinery process is the high cost of the enzymes for the hydrolysis step .…”

Hf-based metal–organic frameworks as acid–base catalysts for the transformation of biomass-derived furanic compounds into chemicals

“…9, 10 Acetone (C3) can be produced from the fermentation of glucose. 11,12 Combination of these components through aldol condensation allows the formation of products in the range of C8-C15 that could be further transformed in liquid alkanes in the fuel range through hydrogenation/dehydration/hydrodeoxygenation reactions. 13 Aldol condensation can be catalyzed by both acids and bases, being most commonly used base catalysts.…”