Different Strategies To Improve Lactic Acid Productivity Based on Microorganism Physiology and Optimum Operating Conditions

Abstract

Despite the broad variety of substrates tested for lactic acid production, most of them have problems, even those with promising results. The use of sugar cane molasses appears as a viable alternative, allowing the development of high-performance lactic acid production with yeast extract. In this study, different strategies are proposed and evaluated to achieve high yield, productivity, and lactic acid concentrations considering the suitable association among strain physiology, osmotic stress, substrates, pH control, and fermentation operational parameters. With these strategies and using molasses as a substrate, it was possible to obtain a yield of 95%, with a productivity of 5.38 g L −1 h −1 , and a titer of 157.95 g/L of lactic acid.

Improvement and Metabolomics-Based Analysis of d-Lactic Acid Production from Agro-Industrial Wastes by Lactobacillus delbrueckii Submitted to Adaptive Laboratory Evolution

“…These results suggested that there might be some other factors that restricted DLA fermentation performance, besides osmotic pressure. Because the sugar in sugarcane molasses is composed of glucose, fructose, and sucrose, 6 we speculated that the lower utilization of fructose and sucrose in sugarcane molasses by L. delbrueckii S−NL31 might be another factor affecting DLA fermentation. To verify our speculation, experiments on DLA fermentation using glucose, fructose, and sucrose as carbon source were performed.…”

“…Sugarcane molasses is a relatively inexpensive industrial byproduct from the sugar-manufacturing process, generally comprising approximately 50% (w/v) of total sugars (sucrose, glucose, and fructose), which has been used for the production of ethanol, succinic acid, and lactic acid. , The output of sugarcane molasses in China is about 3 million tons annually, which makes it an available raw material for microbial production. , However, some hazardous substances and excessive metallic ions are generated during the sugar-manufacturing process, which are toxic to cell growth, causing low conversion yield and productivity . To reduce the levels of various inhibitors and improve sugarcane molasses utilization, additional pretreatments are needed, which increases the workload and fermentation cost.…”

Feasibility of the Conversion of Sugarcane Molasses to Levulinic Acid: Reaction Optimization and Techno-Economic Analysis

“…The sugarcane industry may be identified as a model of circular and renewable economy in which biomass can be converted into sugar, ethanol, electricity, heat, fertilizer, and many other products, such as cellulosic hydrolysate, butanol, lactic acid, and levulinic acid (LA). , Levulinic acid is a γ-keto acid that represents a promising renewable chemical platform. Industrial applications of levulinic acid include fuel additives, paints, plastics, lubricants, food additives, fertilizers, etc. , Currently, most of the research on levulinic acid production from industrial feedstocks is focused on lignocellulosic biomass, ,, although there are examples morefocused on the study of catalysts using glucose, − fructose, ,,− or sucrose as reactants. ,− According to these studies, heterogeneous catalysts provide yields of levulinic acid up to 68 mol %, whereas homogeneous catalysts provide yields up to 80 mol %.…”

“…The yield of sugarcane molasses (SM) is around 35.5 kg per tonne of sugarcane, with an annual production of 50 million tonnes . Usually, sugarcane molasses is fermented to produce ethanol, but other fermentation-based products were already considered, such as methane and lactic acid . Alternatively, the hydrolysis of sugarcane molasses under acidic conditions can be used to produce 5-hydroxymethylfurfural (HMF) and levulinic acid (LA), as shown in Figure , with no use of microorganisms.…”

“…The sugarcane industry may be identified as a model of circular and renewable economy in which biomass can be converted into sugar, ethanol, electricity, heat, fertilizer, and many other products, such as cellulosic hydrolysate, 1 butanol, 2 lactic acid, 3 and levulinic acid (LA). 4,5 Levulinic acid is a γ-keto acid that represents a promising renewable chemical platform.…”