Title : Toward biocatalyzed carbohydrate-based surfactants synthetic strategy: Optimization of biocatalyzed multi-step one-pot synthesis of a biosourced lipophilic moiety
Abstract:
The actual worldwide need for a more sustainable consumption leads conventional chemistry to undergo profound changes to meet nowadays and future challenges, especially processes decarbonization. Biocatalyzed processes can fit with this purpose of more sustainable industrial processes. Considering surfactant-producing industry, especially “green” surfactants (association of a hydrophilic group and a lipophilic moiety), non-ionic biobased fatty acid carbohydrate esters are used in multiple fields, such as cosmetics, food industry, and pharmacology and biocontrol. These multi-applications have created a worldwide market for such bioproducts and consequently expectations for their greener production. In- between hydrophilic and lipophilic groups, a spacer/linker can be introduced to confer additional properties to the surfactant, such as improved amphiphilic properties or a lower CMC (critical micellar concentration) value. Beyond the surfactant aspects, add a spacer would allow to integrate molecular patterns to classical surfactants and thus create a molecule-application relationship, with for example Pathogen-Associated Molecular Patterns (PAMP). The present work, as a part of biocatalyzed synthesis of carbohydrate-based surfactants, deals with the selective biocatalyzed conception of an aglycone, including biosourced spacer and lipophilic synthons, in two steps one-pot synthesis. The purpose is to condense a fatty alcohol onto dicarboxylic acid using a lipase as catalyst. Then, a diol is added to the reaction medium to react with the products obtained in the first step to obtain a monohydroxylated aglycone. A study of the specific substrates involved in the reaction identified the most efficient intermediates. Kinetic study using gas chromatography further enabled us to optimize reaction time and volume for a more efficient process. For example, a maximum yield is obtained after only short time. Various points have been optimized to maximize yields and enzymatic selectivity: lipase origin, temperature, green solvent alternative, co-solvent lipase molecular bio-imprinting. For example, the use of 2-methyltetrahydrofuran-3-one as solvent increased reaction selectivity. We have therefore mapped various parameters and so we can propose a multi-step one-pot synthesis of spacer-lipophilic biosourced synthon in 4h, without treatment. We are now working on the grafting this entity onto carbohydrate using a β-glucosidase, to implement an enzymatic cascade.
Audience Take Away
- How to manage a multi-step biocatalytic synthesis
- How solvents impact enzyme selectivity
- How protein conformational memory can be an interesting tool.
