Microbial Production of Sugar Alcohols

Sugar alcohols, also known as polyols, are organic sugar derivatives and have the general formula HOCH2(CHOH)nCH2OH. These are acyclic hydrogenated forms of sugars but metabolize differentially in our body and thus have a reduced calorie content compared to their sugar counterparts which make them popular sweeteners in the food industry. Arabitol, erythritol, mannitol, sorbitol,, and xylitol are the important sugar alcohols best used in industrial and medical applications due to their exceptional functionality and health benefits. The chemical synthesis of sugar alcohols requires strict reaction conditions such as pure substrates and high-cost chemical catalysts, high pressure and temperature. In addition, the immense processes for the removal of by-products are also a constraint of chemical synthesis. Microbial production of sugar alcohols is a sustainable and cost-effective alternative for the production of sugar alcohols which involves the fermentation of sugars by microorganisms such as bacteria and yeast. Here in this chapter, we discuss the recent advances in the microbial synthesis of sugar alcohols, the latest metabolic engineering aspects and developments, focussing on the microbial fermentation of pure and alternative carbon sources.