Advanced Fermentation Techniques for Lactic Acid Production from Agricultural Waste

Abstract

Lactic acid plays an important role in industrial applications ranging from the food industry to life sciences. The growing demand for lactic acid creates an urgent need to find economical and sustainable substrates for lactic acid production. Agricultural waste is rich in nutrients needed for microbial growth. Fermentative production of lactic acid from non-food-competing agricultural waste could reduce the cost of lactic acid production while addressing environmental concerns. This work provided an overview of lactic acid fermentation from different agricultural wastes. Although conventional fermentation approaches have been widely applied for decades, there are ongoing efforts toward enhanced lactic acid fermentation to meet the requirements of industrial productions and applications. In addition, agricultural waste contains a large proportion of pentose sugars. Most lactic-acid-producing microorganisms cannot utilize such reducing sugars. Therefore, advanced fermentation techniques are also discussed specifically for using agricultural waste feedstocks. This review provides valuable references and technical supports for the industrialization of lactic acid production from renewable materials.

Harnessing Agri-Food Waste as a Source of Biopolymers for Agriculture

“…The optimization of the use of AFW as fermentation substrates to produce LA is crucial for both a waste valorization approach and for the cost reduction of the process [113]. Before the fermentation step, the biomass typically undergoes a pre-treatment, which may be physical, biological, chemical, or a combination of these methods: this is because agricultural by-products, which are usually lignocellulosic, need to be delignified and saccharified for the microorganism to use them as substrates [114]. Alternatively, the process needs to employ a microorganism with both the capacity to degrade complex lignocellulosic biomasses and to produce LA; this approach is called consolidated bioprocessing (CBP) [115].…”

Microbial production of stereospecific lactic acid from sugarcane trash hydrolysate with no pre-detoxification step

“…LA fermentation processes conventionally utilize refined sugar and starch as substrates, constituting a significant proportion of the total production cost. To reduce production costs, the use of alternative raw materials such as agricultural wastes or lignocellulosic biomass, a zero-carbon and renewable feedstock that contributes to the reduction of global warming, has garnered increasing interest (Ahmad et al, 2020;Huang et al, 2023a). However, the use of lignocellulosic material introduces a potential challenge, as the release of toxic by-products during processing can impede the efficiency of the fermentation process.…”