Identifying inhibitory effects of lignocellulosic by-products on growth of lactic acid producing micro-organisms
Edwin C van der Pol1, Evelien Vaessen2, Ruud A Weusthuis2
1Food and Biobased Research, Wageningen University and Research Centre, PO Box 17, 6700 AA Wageningen, Netherlands; Bioprocess Engineering, Wageningen University and Research Centre, PO Box 16, 6700 AA Wageningen, Netherlands.
Abstract:
Sugars obtained from pretreated lignocellulose are interesting as substrate for the production of lactic acid in fermentation processes. However, by-products formed during pretreatment of lignocellulose can inhibit microbial growth. In this study, a small-scale rapid screening method was used to identify inhibitory effects of single and combined by-products on growth of lactic acid producing micro-organisms. The small-scale screening was performed in 48-well plates using 5 bacterial species and 12 by-products. Large differences were observed in inhibitory effects of by-products between different species. Predictions can be made for growth behaviour of different micro-organisms on acid pretreated or alkaline pretreated bagasse substrates using data from the small-scale screening. Both individual and combined inhibition effects were shown to be important parameters to predict growth. Synergy between coumaric acid, formic acid and acetic acid is a key inhibitory parameter in alkaline pretreated lignocellulose, while furfural is a key inhibitor in acid pretreated lignocellulose.
