Abstract
Lactic acid (LA) production is already a global reality. Its applications cover the most diverse industrial sectors and have rapidly consolidated in recent years. Currently, the most prominent use of LA is the production of polylactic acid to replace plastics from the petrochemical industry. A great part of this rapid change is due to the rising worldwide concerns about the excess of non-degradable plastics used daily and the accumulation of this material in nature. In this scenario, LA production becomes even more relevant when considering its production from renewable raw materials, especially second-generation (2G) substrates, such as lignocellulosic biomass. This reduces the human dependence on oil for both energy and fuel production, as well as for the production of plastics and other chemicals since LA is still one of the most relevant building block chemicals. Nowadays it is possible to produce LA from the most diverse 2G-substrates available around the world. Thus, LA production by fermentation of 2G-sugars can be associated with several existing biorefinery models, such as for biofuels and chemicals production. In this scenario, for example, it is possible to associate LA production with ethanol production in a biorefinery model, producing 1G-ethanol, 2G-LA, sugar for food, and electricity. This kind of approach may represent a break from current production model of energy and chemicals to a more sustainable and democratic scenario, including new players in the world market and reducing the dependence of other countries to supply oil and its derivates, especially when associated with new and powerful genetic engineering tools. Front this scenario, this review presents the state of the art of 2G-LA production.
