3-98: Selecting microbial production hosts for lignocellulosic feedstock utilization

Increasingly, lignocellulosic biomass is used to make fermentation processes more cost-effective and, at the same time, more environmentally friendly. Currently, the choice for the production organisms is mostly based on prior experience working with a specific host and not on their suitability to utilize ‘real life’ feedstocks. Wild-type strains of six industrial relevant microbial production hosts (2 fungi, 2 yeasts and 2 bacteria) were evaluated for their performance on lignocellulosic feedstocks. The renewable feedstocks tested included corn stover, wheat straw, bagasse and willow. The biomass feedstocks were generated in two manners: (1) thermal treatment under mild acid conditions followed by enzymatic hydrolysis and (2) concentrated acid pretreatment and hydrolysis (the Biosulfurol process). Moreover, waste glycerol was included in the study. The six microorganisms were evaluated for ‘real life’ feedstock and carbon source utilization, resistance against feedstock-related inhibitors, and general fermentation and process characteristics on the ‘real life’ feedstocks. Large differences in the overall performance of the six tested microbial production host on feedstocks were observed. Aspergillus niger and Pichia stipitis were found to perform best. This study will be extended with 4 more pretreatment methods: dilute acid, alkali (lime), steam explosion and ammonia fibre explosion, thus creating a lignocellulosic biomass pretreatment platform.