Complete Carbon-LA - Lactic acid from the entire biomass

Research Project, 2023 – 2026

Lignocellulosic hydrolysate made from forest-based or agricultural waste biomass has so far not been widely exploited in biotechnological production processes, mainly due to toxicity for the production hosts. Furthermore, the pentose sugars can typically not be used in yeast-based process. We introduce solutions for these bottlenecks, material toxicity and inefficient carbon utilization and develop a sustainable process for production of lactic acid.Our production process is based on the yeast Saccharomyces cerevisiae, which we have developed into efficiently producing lactic acid from pure xylose. A bottleneck with this strain is that in presence of glucose, it mainly produces ethanol. We have collected transcriptomic data for different S. cerevisiae strains growing on lignocellulosic hydrolysate, data that we aim to exploit for improving the tolerance towards this raw material. We intend to engineer the yeast to detoxify the material as it utilizes the inhibiting compounds as carbon sources. We will also introduce pathways for converting arabinose and engineer more efficient up-take of pentoses. In addition, we will work with the development of a process where we also use lactic acid bacteria that by nature can convert glucose to lactic acid, while these bacteria cannot use xylose. Thus, a co-culture of two microorganisms that complement each other can lead to a higher yield of lactic acid. The goal is to form a closed system, where all carbon is converted to lactic acid.