Biotechnological advances in lactic acid production by lactic acid bacteria: lignocellulose as novel substrate

Abstract

The production of high added-value products from lignocellulose is proposed as a suitable alternative to petroleum-based resources in terms of environmental preservation, sustainability, and circular economy. Lactic acid is a versatile building block that can be produced via fermentative routes by several groups of microorganisms, including yeasts and microalgae, which are bacteria recognized to achieve the highest concentrations. Lactic acid, among other substances, can be used as a starting point in the production of poly-lactic acid, which is a biopolymer with many applications due to its resistance, durability, biodegradability, and biocompatibility. Lactic acid production can be performed from lignocellulosic biomass. However, lactic acid production from lignocellulose faces several hurdles such as carbohydrate hydrolysis to release sugars, the co-utilization of sugar mixtures by the fermenting microorganism, and the presence of degradation compounds released during pretreatment. In this review, a general overview of lactic-acid bacterial fermentation from lignocellulose is provided, starting from the potential substrates and their composition, the different metabolic pathways involved, and the purifi cation steps. The main challenges are discussed and the newest approaches to solve the limitations of the process are proposed.

Current advances in organic acid production from organic wastes by using microbial co‐cultivation systems

“…) is an important platform chemical. The worldwide demand for lactic acid is expected to reach 1960 kt by 2020 . Although the technology for bio‐lactic acid production is very mature, the cost of traditional substrates limits its application.…”

Lactobacillus pentosus CECT 4023 T co‐utilizes glucose and xylose to produce lactic acid from wheat straw hydrolysate: Anaerobiosis as a key factor

“…Furthermore, the industrial applications of this acid are dependent on the LA isomer produced. While L‐LA is preferred in food and pharmaceutical industries, both optically pure D‐LA and L‐LA are used for the production of different chemicals and PLA polymers . LA can be produced by chemical or by microbial processes.…”

Microbial production of d‐lactic acid from dried distiller's grains with solubles

“…Specifically, agricultural residues such as corn stover [18,19], rice bran [20], peanut meal [21], broken rice [22], and unpolished rice [23] have been studied as potential carbon sources for lactic acid production. Besides, fermentation broths derived from renewable sources also contain a mixture of compounds, including a variety of sugars and proteins, degraded compound from pretreatment, polyphenols and organic acids, and thus require an effective downstream processing for the recovery of the lactic acid [24,25]. Most of the homofermentative d-lactic acid producers (i.e., Lactobacillus sp.…”

“…However, the hydrolysis of biomass materials, that are rich in cellulose/hemicellulose, produces a mixture of sugar monomers such as glucose, xylose, mannose, arabinose, and galactose. Several methods such as precipitation, extraction, crystallization, ion exchange, adsorption, membrane filtration, distillation, and nanofiltration can be used to recover lactic acid from fermentation broth [17,25]. and Sporolactobacillus sp.)…”

“…The enzymatic approach is preferred to chemical hydrolysis, as the reactions are more specific and less hazardous [25,26]. The enzymatic approach is preferred to chemical hydrolysis, as the reactions are more specific and less hazardous [25,26].…”