Recently, lactic acid production from renewable materials has gained enormous attention due to the several functional properties it offers in different fields. The high yield productivity of lactic acid by utilizing economical and easily available substrates has received immense attraction in the petrochemical industry. Biomass or waste materials from various sources have become a significant concern because they cause severe environmental pollution if disposed of improperly. Hence, the employment of an integrated biorefinery platform for waste materials is an ideal option to produce high-value bio-products while remediating the waste. Optical pure lactic acid production through fermentation has gained interest due to its high potential applications in food, pharmaceutical, textiles, and cosmetic industries as well as highly promising packaging materials. The manufacturing of biodegradable bioplastic from polylactic acid materials is a green alternative to that derived from petrochemicals. However, high manufacturing costs have impeded the widespread application of polylactic acid due to the high cost of lactic acid production. This review paper summarizes the most recent advancements and challenges in pure lactic acid production from various substrates and conventional processes, including pretreatment and enzymes hydrolysis and fermentative technologies. Moreover, a detailed analysis of the techno-economic feasibility, downstream processing, and lactic acid purification techniques are also discussed.

A review on the lactic acid fermentation from low-cost renewable materials: Recent developments and challenges

Xylooligosaccharides: Transforming the lignocellulosic biomasses into valuable 5-carbon sugar prebiotics

Xylooligosaccharides production by commercial enzyme mixture from agricultural wastes and their prebiotic and antioxidant potential

Anaerobic digestion of organic waste: Recovery of value-added and inhibitory compounds from liquid fraction of digestate.

Soybean protein (Pro) and soybean oligopeptide (Pep) were subjected to simulated digestion in vitro to study the effect of Pep on the growth and metabolism of Lactobacillus acidophilus JCM 1132. First, the molecular weight distribution differences of samples before and after digestion were compared, and the samples were used to replace the nitrogen source components in the culture media. Then, the viable cell numbers, lactic acid and acetic acid content, differential metabolites, and metabolic pathways during the culturing process were measured. Results showed that the digested soybean oligopeptide (dPep) was less efficient than MRS medium in promoting the growth, but by increasing the content of the intermediates during the tricarboxylic acid (TCA) cycle, its metabolic capacity was significantly improved. Besides, due to the low molecular weight of dPep, it can be better transported and utilized. And dPep significantly strengthened the amino acid metabolism and weakened the glycerol phospholipid metabolism, so the ability of dPep in promoting the growth and metabolism of Lactobacillus acidophilus JCM 1132 is higher than the digested soybean protein (dPro).

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Effect of soybean oligopeptide on the growth and metabolism of Lactobacillus acidophilus JCM 1132

The concern about food quality and diseases prevention has increased the number of researches aimed at improving health by modulating the intestinal microbiota. Such modulation can be achieved by ingesting prebiotic ingredients and probiotics. In the present work, “in vitro” digestion of commercial fructooligosaccharides (FOs) and xylooligosaccharides (XOs) by gastrointestinal tract enzymes was performed, as well as “in vitro” growth of Bifidobacterium, Lactobacillus and Salmonella. The digestibility tests confirmed the resistance of commercial XOs and FOs to gastrointestinal enzymes and to the acidity of gastric juice. Growth experiments indicated the ability of Lactobacillus acidophilus and Bifidobacterium lactis to ferment FOs. Lactobacillus brevis and Bifidobacterium breve showed preference for XOs while Bifidobacterium longum grew using both carbon sources and Bifidobacterium animalis did not grow in any of them. Regarding Salmonella typhimurium, in 4 h, no bacterial growth in the cultures with oligosaccharides was observed, suggesting the selectivity of these prebiotics by probiotic bacteria. These results show the different responses of prebiotics for each probiotic strain. A mixture of prebiotics that increase the efficiency of distinct probiotics is important and should be considered for food and feed applications.

Evaluation of xylooligosaccharides and fructooligosaccharides on digestive enzymes hydrolysis and as a nutrient for different probiotics and Salmonella typhimurium

The substrate cost is a hurdle in the lactic acid (LA) manufacturing by microbial fermentations Thus, this work aimed to optimize the production of LA by Lactobacillus amylovorus and Lactobacillus acidophilus in a culture medium containing agro-industrial wastes, cassava bagasse (CB, 6–18%, w/v) and corn steep liquor (CSL, 4–12%, v/v) Initially, the optimal medium composition was defined; different fermentation times were also assessed CB was used in natura or hydrolyzed by Rhizopus oligosporus' amylase In a batch process without pH control, the LA maximum concentration (316 g/L) and productivity (011 g L ⋅ h ) were obtained by L amylovorus using 14% (w/v) hydrolyzed CB and 10% (v/v) CSL However, when a Fed-batch process was performed with pH control and using the optimized culture medium composition, high volumetric productivity (046 g L ⋅ h ) was achieved The optimized medium's cost is 005 US$/L These findings suggest a promising bioprocess for LA manufacturing from agro-industrial wastes

Fabiane Fernanda de Barros Ranke

Papers

Evaluation of xylooligosaccharides and fructooligosaccharides on digestive enzymes hydrolysis and as a nutrient for different probiotics and Salmonella typhimurium

Cost-effective lactic acid production by fermentation of agro-industrial residues

Ethanol from rice byproduct using amylases secreted by Rhizopus microsporus var. oligosporus. Enzyme partial purification and characterization.

Bioprocess development with special yeasts for cassava bagasse enrichment nutritional to use in animal feed