Recent advances in lactic acid production by microbial fermentation processes

An economic evaluation of the fermentative production of lactic acid from wheat flour

Publisher Summary The chapter focuses on the production of lactic acid by microbiological processes. It discusses the chemical and physical properties of the acid followed by its commercial uses. Lactic acid, 2-hydroxypropanoic acid or α-hydroxypropanoic acid, is served as a food preservative in fermented milks, fruits, vegetables, meats, and breads. Various carbohydrate raw materials are used for lactic acid production by bacteria and molds such as refined carbohydrate raw materials; glucose, sucrose, and starch; complex carbohydrates—cellulose, cereal grains, corn, Jerusalem artichokes, and potatoes; and waste materials—cheese whey and permeate, municipal solid waste, and wood molasses. Factors affecting lactic acid concentrations, productivities, and yields include types of process (batch, fed-batch, or continuous), microorganism, strain, inoculum size and nutritional state, temperature, pH, substrate concentration and pretreatment, the presence of competing contaminants in non sterile systems, the presence of bacteriophages, and inhibition by lactic acid with increasing concentrations and by toxic products from substrate pretreatment such as furfural and hydroxymethylfurfural. The chapter also discusses various methods of product recovery and purification namely precipitation and acidification, centrifugation and microfiltration/ultrfiltration, distillation, ion exchange and adsorption, reverse osmosis, and solvent extraction and extractive fermentation. Various types of process controls are also summarized.

Microbiological production of lactic acid.

Integrated processing of biotechnology products.

Gel entrapment and micro-encapsulation: methods, applications and engineering principles

A continuous stirred tank reactor (CSTR) with cell recycle was used to produce lactic acid from glucose usingLactobacillus delbreuckii NRRLB445. A volumetric productivity of 76 gm/1-h was obtained with an effluent concentration of 35 gm/1 lactic acid and a residual glucose concentration of less than 0.02 gm/l.

D. K. Dea

Papers

The application of cell recycle to continuous fermentative lactic acid production