Utilization of renewables for lactic acid fermentation.

Area of Science:

• Biotechnology
• Microbiology
• Sustainable Chemistry

Background:

• Lactic acid production traditionally uses pure glucose.
• Agricultural feedstocks like grains and green biomass are emerging as sustainable raw materials.
• Optimizing fermentation processes is key for efficient bio-based production.

Purpose of the Study:

• To select a high-productivity lactic acid bacterium strain.
• To optimize batch fermentation parameters for lactic acid production.
• To evaluate the use of agricultural feedstocks, specifically barley hydrolysate and green biomass, as nutrient sources.

Main Methods:

• Selection and cultivation of a high-productivity Lactobacillus paracasei strain.
• Optimization of batch fermentation process parameters on a laboratory scale.
• Medium optimization, including replacement of synthetic nutrients with protein extracts from lucerne green juice.

Main Results:

• The selected Lactobacillus paracasei strain achieved high lactic acid accumulation (>100 g/L) in a complex nutrient broth.
• Protein extracts from lucerne green juice effectively replaced peptone and yeast extract, essential nitrogen sources.
• Substitution of synthetic nutrients with renewable resources (barley hydrolysate, green biomass) did not reduce productivity.

Conclusions:

• Sustainable lactic acid production is feasible using agricultural feedstocks and green biomass.
• Renewable resources can substitute synthetic nutrients without compromising fermentation productivity.
• Further optimization using high biomass concentration and cell density could enhance lactic acid production.