1. Martinez, F. A. C. et al. Lactic acid properties, applications and production: A review. Trends Food Sci. Technol. 30, 70–83 (2013).
2. Becker, J., Lange, A., Fabarius, J. & Wittmann, C. Top value platform chemicals: Bio-based production of organic acids. Curr. Opin. Biotechnol. 36, 168–175 (2015).
3. Choi, S., Song, C. W., Shin, J. H. & Lee, S. Y. Biorefineries for the production of top building block chemicals and their derivatives. Metab. Eng. 28, 223–239 (2015).
4. Ajala, E. O., Olonade, Y. O., Ajala, M. A. & Akinpelu, G. S. Lactic acid production from lignocellulose—A review of major chal- lenges and selected solutions. ChemBioEng Rev. https://doi.org/10.1002/cben.201900018 (2020).
5. Nduko, J. M. & Taguchi, S. Microbial production and properties of LA-based polymers and oligomers from renewable feedstock. In Production of Materials from Sustainable Biomass Resources (eds. Fang, Z., Smith, R. L. & Tian, X.-F.) 361–390 (Springer Singapore, 2019). https://doi.org/10.1007/978-981-13-3768-0_12.
6. Dusselier, M., Van Wouwe, P., Dewaele, A., Makshina, E. & Sels, B. F. Lactic acid as a platform chemical in the biobased economy: The role of chemocatalysis. Energy Environ. Sci. 6, 1415 (2013).
7. Kim, J. et al. Lactic acid production from a whole slurry of acid-pretreated spent coffee grounds by engineered Saccharomyces cerevisiae. Appl. Biochem. Biotechnol. 189, 206–216 (2019).
8. Chen, H. et al. Efficient lactic acid production from cassava bagasse by mixed culture of Bacillus coagulans and Lactobacillus rhamnosus using stepwise pH controlled simultaneous saccharification and co-fermentation. Ind. Crops Prod. 146, 112175 (2020).
9. Tian, X., Hu, W., Chen, J., Zhang, W. & Li, W. The supplement of vitamin C facilitates L-lactic acid biosynthesis in Lactobacillus thermophilus A69 from sweet sorghum juice coupled with soybean hydrolysate as feedstocks. Ind. Crops Prod. 146, 112159 (2020).
10. de Matos, M., Santos, F. & Eichler, P. Sugarcane world scenario. In Sugarcane Biorefinery, Technology and Perspectives 1–19 (Elsevier, 2020). https://doi.org/10.1016/B978-0-12-814236-3.00001-9.
11. Cortez, L. A. B., Baldassin, R. & De Almeida, E. Energy from sugarcane. Sugarcane Biorefinery Technol. Perspect. https://doi.org/ 10.1016/B978-0-12-814236-3.00007-X (2020).
12. Ling, H., Teo, W., Chen, B., Leong, S. S. J. & Chang, M. W. Microbial tolerance engineering toward biochemical production: From lignocellulose to products. Curr. Opin. Biotechnol. 29, 99–106 (2014).
13. Palmqvist, E. & Hahn-Hägerdal, B. Fermentation of lignocellulosic hydrolysates. I: inhibition and detoxification. Bioresour. Technol. 74, 17–24 (2000).
14. Hahn-Hägerdal, B., Karhumaa, K., Fonseca, C., Spencer-Martins, I. & Gorwa-Grauslund, M. F. Towards industrial pentose- fermenting yeast strains. Appl. Microbiol. Biotechnol. 74, 937–953 (2007).
15. Yang, P.-B., Tian, Y., Wang, Q. & Cong, W. Effect of different types of calcium carbonate on the lactic acid fermentation performance of Lactobacillus lactis. Biochem. Eng. J. 98, 38–46 (2015).
16. Qin, J. et al. Production of l-lactic acid by a thermophilic Bacillus mutant using sodium hydroxide as neutralizing agent. Bioresour. Technol. 101, 7570–7576 (2010).
17. Hetényi, K., Németh, Á. & Sevella, B. Role of pH-regulation in lactic acid fermentation: Second steps in a process improvement. Chem. Eng. Process. Process Intensif. 50, 293–299 (2011).
18. Komesu, A., Wolf Maciel, M. R., Rocha de Oliveira, J. A., da Silva Martins, L. H. & Maciel Filho, R. Purification of lactic acid produced by fermentation: Focus on non-traditional distillation processes. Sep. Purif. Rev. 46, 241–254 (2017).
19. Hasunuma, T., Ismail, K. S. K., Nambu, Y. & Kondo, A. Co-expression of TAL1 and ADH1 in recombinant xylose-fermenting Sac- charomyces cerevisiae improves ethanol production from lignocellulosic hydrolysates in the presence of furfural. J. Biosci. Bioeng. 117, 165–169 (2014).
20. Suzuki, T. et al. Disruption of multiple genes whose deletion causes lactic-acid resistance improves lactic-acid resistance and productivity in Saccharomyces cerevisiae. J. Biosci. Bioeng. 115, 467–474 (2013).
21. Brandt, B. A., García-Aparicio, M. D. P., Görgens, J. F. & van Zyl, W. H. Rational engineering of Saccharomyces cerevisiae towards improved tolerance to multiple inhibitors in lignocellulose fermentations. Biotechnol. Biofuels 14, 1–18 (2021).
22. Cámara, E. et al. Data mining of Saccharomyces cerevisiae mutants engineered for increased tolerance towards inhibitors in ligno- cellulosic hydrolysates. Biotechnol. Adv. 57, 107947 (2022).
23. Kahar, P. et al. Challenges of non-flocculating Saccharomyces cerevisiae haploid strain against inhibitory chemical complex for ethanol production. Bioresour. Technol. 245, 1436–1446 (2017).
24. Kahar, P. et al. The flocculant Saccharomyces cerevisiae strain gains robustness via alteration of the cell wall hydrophobicity. Metab. Eng. 72, 82–96 (2022).
25. Ishida, N. et al. Efficient production of l-lactic acid by metabolically engineered Saccharomyces cerevisiae with a genome-integrated l-lactate dehydrogenase gene. Appl. Environ. Microbiol. 71, 1964–1970 (2005).
26. van Maris, A. J. A. et al. Directed evolution of pyruvate decarboxylase-negative Saccharomyces cerevisiae, yielding a C2-independent, glucose-tolerant, and pyruvate-hyperproducing yeast. Appl. Environ. Microbiol. 70, 159–166 (2004).
27. Hohmann, S. PDC6, a weakly expressed pyruvate decarboxylase gene from yeast, is activated when fused spontaneously under the control of the PDC1 promoter. Curr. Genet. 20, 373–378 (1991).
28. Tokuhiro, K. et al. Double mutation of the PDC1 and ADH1 genes improves lactate production in the yeast Saccharomyces cerevisiae expressing the bovine lactate dehydrogenase gene. Appl. Microbiol. Biotechnol. 82, 883–890 (2009).
29. Baek, S.-H., Kwon, E. Y., Kim, Y. H. & Hahn, J.-S. Metabolic engineering and adaptive evolution for efficient production of d-lactic acid in Saccharomyces cerevisiae. Appl. Microbiol. Biotechnol. 100, 2737–2748 (2016).
30. Baek, S.-H. et al. Improvement of d-lactic acid production in Saccharomyces cerevisiae under acidic conditions by evolutionary and rational metabolic engineering. Biotechnol. J. 12, 1700015 (2017).
31. Saitoh, S. et al. Genetically engineered wine yeast produces a high concentration of l-lactic acid of extremely high optical purity. Appl. Environ. Microbiol. 71, 2789–2792 (2005).
32. Peng, B., Williams, T. C., Henry, M., Nielsen, L. K. & Vickers, C. E. Controlling heterologous gene expression in yeast cell factories on different carbon substrates and across the diauxic shift: A comparison of yeast promoter activities. Microb. Cell Fact. 14, 91 (2015).
33. Balbas, P. & Lorence, A. Recombinant Gene Expression. vol. 267 (Humana Press, 2004).
34. Park, H. J. et al. Low-pH production of d-lactic acid using newly isolated acid tolerant yeast Pichia kudriavzevii NG7. Biotechnol. Bioeng. 115, 2232–2242 (2018).
35. Ilmén, M. et al. Production of l-lactic acid by the yeast Candida sonorensis expressing heterologous bacterial and fungal lactate dehydrogenases. Microb. Cell Fact. 12, 53 (2013).
36. Mitsui, R. et al. Construction of lactic acid-tolerant Saccharomyces cerevisiae by using CRISPR-Cas-mediated genome evolution for efficient d-lactic acid production. Appl. Microbiol. Biotechnol. 104, 9147–9158 (2020).
37. Jang, B. K. et al. l-lactic acid production using engineered Saccharomyces cerevisiae with improved organic acid tolerance. J. Fungi 7, 928 (2021).
38. van der Pol, E. C., Eggink, G. & Weusthuis, R. A. Production of l(+)-lactic acid from acid pretreated sugarcane bagasse using Bacillus coagulans DSM2314 in a simultaneous saccharification and fermentation strategy. Biotechnol. Biofuels 9, 248 (2016).
39. Unrean, P. Optimized feeding schemes of simultaneous saccharification and fermentation process for high lactic acid titer from sugarcane bagasse. Ind. Crops Prod. 111, 660–666 (2018).
40. de Oliveira, R. A., Schneider, R., Vaz Rossell, C. E., Maciel Filho, R. & Venus, J. Polymer grade l-lactic acid production from sugarcane bagasse hemicellulosic hydrolysate using Bacillus coagulans. Bioresour. Technol. Rep. 6, 26–31 (2019).
41. Baral, P., Pundir, A., Kumar, V., Kurmi, A. K. & Agrawal, D. Expeditious production of concentrated glucose-rich hydrolysate from sugarcane bagasse and its fermentation to lactic acid with high productivity. Food Bioprod. Process. 124, 72–81 (2020).
42. Kato, M. & Lin, S.-J. Regulation of NAD+ metabolism, signaling and compartmentalization in the yeast Saccharomyces cerevisiae. DNA Repair (Amst). 23, 49–58 (2014).
43. Massudi, H., Grant, R., Guillemin, G. J. & Braidy, N. NAD+ metabolism and oxidative stress: The golden nucleotide on a crown of thorns. Redox Rep. https://doi.org/10.1179/1351000212Y.0000000001 (2012).
44. Daful, A. G. & Görgens, J. F. Techno-economic analysis and environmental impact assessment of lignocellulosic lactic acid produc- tion. Chem. Eng. Sci. 162, 53–65 (2017).
45. Zhao, E. M. et al. Optogenetic regulation of engineered cellular metabolism for microbial chemical production. Nature 555, 683–687 (2018).
46. Gietz, R. & Woods, R. A. Transformation of yeast by lithium acetate/single-stranded carrier DNA/polyethylene glycol method. Methods Enzymol. 350, 87–96 (2002).