Computer-aided engineering of lipases solvent tolerance enhanced their applications in sugar esters synthesis: State of the art

Sugar esters (SEs) are non-ionic amphiphilic surfactants that possess excellent emulsifying properties, and consequently have potential applications in the food, pharmaceutical, and other related industries. In the food sector, SEs are particularly attractive, due to their reported effective usage in dessert processing, fruit and vegetable preservation, and as an antibacterial agent. In this review, the chemical and enzymatic methods for the synthesis of SEs were highlighted, and the efficiency of enzymatic synthesis was explored based on solvent tolerance. While traditional chemical synthesis has been simplified and made more efficient, it still necessitates the use of high temperature and pressure, resulting in low selectivity and potential environmental impact. The enzymatic synthesis of SEs has become increasingly popular due to its high regional selectivity and sustainable reaction conditions. Nonetheless, this method's further implementation in the food industry is hindered by the lower solvent tolerance of most lipases in organic solvents. The strategies for solvent-tolerance engineering of lipase based on computational assistance methods were discussed from insights of hydration-shell, salt bridges, interactions (van der Waals, hydrogen bonds, and hydrophobic interactions), active sites, and solvent tunnels. Finally, several practical and commonly used strategies were summarized and compared, which provides some guidance and theoretical basis for further applications of enzymatic methods in the synthesis of SEs.