Recent advances in biological production of sugar alcohols.

Sugar alcohols, such as xylitol, mannitol, sorbitol, and erythritol are emerging food ingredients that provide similar or better sweetness/sensory properties of sucrose, but are less calorigenic. Also, sugar alcohols can be converted into commodity chemicals through chemical catalysis. Biotechnological production offers the safe and sustainable supply of sugar alcohols from renewable biomass. In contrast to early studies that aimed to produce sugar alcohols with microorganisms capable of producing sugar alcohols naturally, recent studies have focused on rational engineering of metabolic pathways to improve yield and productivity as well as to use inexpensive and abundant substrates. Metabolic engineering strategies to utilize inexpensive substrates, alleviate catabolite repression, reduce byproduct formation, and manipulate redox balances led to enhanced production of sugar alcohols.