International Journal of Applied Science and Technology Vol. 5, No. 1; February 2015 164 Lactic Acid Production from Biomass: Prospect for Bioresidue Utilization in Ghana: Technological Review Richard Bayitse Council for Scientific and Industrial Research Institute of Industrial Research (CSIR-IIR) P.O. Box LG. 576, Legon, Ghana Abstract The production of lactic acid from fossil fuel is now widely accepted as unsustainable due to depleting resources and the accumulation of environmentally hazardous chemicals. Cheap raw material is one of the key inputs to cost effective production of Lactic acid. This paper reviews current research in lactic acid fermentation processes, bio-residue availability in Ghana and potential utilization for lactic acid production. Bio-renewable residue has been widely studied and employed due to its abundance and cost. Various fermentation technologies have been employed using fungi and lactic acid bacteria to generate different yields of lactic acid. Both starchy and lignocellulosic biomass have been extensively used, however lignocellulosic biomass in Ghana is generated in large volumes as crop residues and mostly considered waste although some amount is used as animal feed. These crop residues are readily available as cheap raw materials for lactic acid production. Cereal crop residues offer the highest potential for lactic acid production in Ghana. By employing appropriate fermentation processes about 199,856 tonnes, 244,305 tonnes, 127,715 tonnes and 362,003 tonnes of lactic acid at 50 % utilization can be generated from maize cobs, millet stalk, sorghum stalk and rice straw respectively for the international market. Keywords: Lactic acid; Batch; Fermentation; Fed-batch; Biomass; Amylolytic 1.0 Introduction Lactic acid (2-hydroxypropanoic acid), CH 3 CHOHCOOH is the most widely occurring hydroxycarboxylic acid. It was first discovered in 1780 by the Swedish chemist Scheele (Rathin Datta & Henry, 2006). Lactic acid occurred naturally as organic acid and can be produced by fermentation or chemical synthesis. It is present in many foods both naturally or as a product of in situ microbial fermentation, as in sauerkraut, yogurt, buttermilk, sourdough breads and many other fermented foods. Lactic acid is also a major metabolic intermediate in most living organisms, from anaerobic prokaryotes to humans (Datta & Henry, 2006). Lactic acid exists naturally in two optical isomers: d(−)- lactic acid and l(+)-lactic acid. Since elevated levels of the d-isomer are harmful to humans, l(+)-lactic acid is the preferred isomer for food-related and pharmaceutical industries (Datta, 1995). By 1990, global annual production of lacticacid had increased to approximately 40,000 t with two significant producers, CCA Biochem in The Netherlands, with subsidiaries in Brazil and Spain, and Sterling Chemicals in Texas City, TX, USA, as the primary manufacturers. Different technologies and feedstocks are employed. CCA used carbohydrate feedstocks and fermentation technology whiles Sterling used a chemical technology (Datta & Henry, 2006). Lactic acid as a chemical is also considered a commodity with a growing market. Chemical synthesis of lactic acid results in a racemic mixture of the two isomers, while the fermentation process can yield an optically pure form of lactic acid or racemate, depending on microorganisms, substrates and fermentation conditions employed in the production process (Yin et al., 1997). It is usually used in food industry as mild acid flavour, pH regulator or as a preservative. Poly lactic acid (PLA), an emerging product from lactic acid is used in the manufacture of biodegradable plastics. Fermentation of glucose from starch hydrolysate is the new production process for lactic acid. This state-of-the- art production process has replaced the older chemical synthesis, e.g. the addition of hydrogen cyanide to acetaldehyde and the subsequent hydrolysis of the resulting lactonitrile.