Valorisation of food residues would greatly benefit from development of robust processes that create added value compared to current feed- and biogas applications. Recent advances in membrane-bioreactor-based open mixed microbial cultures, enable robust conversion of fluctuating streams of food residues to a mixture of volatile fatty acids (VFAs). In this study, such a mixed stream of VFAs was investigated as a substrate for Escherichia coli, a well-studied organism suitable for application in further conversion of the acids into compounds of higher value, and/or that are easier to separate from the aqueous medium. E. coli was cultured in batch on a VFA-rich anaerobic digest of food residues, tolerating up to 40 mM of total VFAs without any reduction in growth rate. In carbon-limited chemostats of E. coli W3110 ΔFadR on a simulated VFA mixture, the straight-chain VFAs (C₂-C₆) in the mixture were readily consumed simultaneously. At a dilution rate of 0.1 h⁻¹, mainly acetic-, propionic- and caproic acid were consumed, while consumption of all the provided acids were observed at 0.05 h⁻¹. Interestingly, also the branched isovaleric acid was consumed through a hitherto unknown mechanism. In total, up to 80% of the carbon from the supplied VFAs was consumed by the cells, and approximately 2.7% was excreted as nucleotide precursors in the medium. These results suggest that VFAs derived from food residues are a promising substrate for E. coli.

与当前的饲料和沼气应用相比，食品残渣的重估将受益于健壮工艺的发展，这些工艺可创造附加值。基于膜生物反应器的开放式混合微生物培养物的最新进展使波动的食物残渣流能够可靠地转化为挥发性脂肪酸（VFA）的混合物。在这项研究中，研究了这种VFA的混合流作为大肠杆菌的底物，大肠杆菌是一种经过充分研究的有机体，适用于将酸进一步转化为价值更高的化合物，和/或更易于与水分离的化合物。中。大肠杆菌在富含VFA的食物残渣厌氧消化物中分批培养番茄，可耐受40 mM的总VFA，而不会降低生长速度。在模拟的VFA混合物上的大肠杆菌W3110ΔFadR的碳限制化学稳定剂中，混合物中的直链VFA（C ₂ -C ₆）易于同时消耗。在0.1 h ^-1的稀释速率下，主要消耗乙酸，丙酸和己酸，而在0.05 h ^-1观察到所有提供的酸均被消耗。。有趣的是，支链异戊酸也是通过迄今未知的机制被消耗的。总共，供应的VFA中高达80％的碳被细胞消耗，大约2.7％的核苷酸前体作为培养基中的前体被排出。这些结果表明，源自食物残渣的VFA是大肠杆菌的有希望的底物。