K. phaffii modifications to improve lactic acid production, from the selection of clones tolerant to acid to genetic engineering. This is based on the GLp strain constructed by our group by deleting (red) PDC1 and inserting (green) the gene of the bovine L-LDH. Other changes in the yeast genotype that have been attempted include the deletion of GPD1 and of MPC1 [39,40,41]. See text for details. Legend: G3P, glycerol-3-phosphate; DHAP, dihydroxyacetone-phosphate; GA3P, glyceraldehyde-3-phosphate; 1,3BPG, 1,3-bisphosphoglycerate; PEP, phosphoenolpyruvate; F1,6BP, fructose-1,6-bisphosphate; ATP, adenine triphosphate; ADP, adenine diphosphate; NADH/NAD+, nicotinamide adenine dinucleotide; G6P, glucose 6-phosphate; RL5P, ribulose 5-phosphate; RL, ribulose; F1,6BP, fructose 1,6-bisphosphate. Made with BioRender.