COSMETICS & PERSONAL CARE family. Hydrolases— including lipases, esterases, proteases and glycosidases— generally catalyse the cleavage or formation of ester, peptide or glycosidic bonds. Many hydrolases employ a catalytic triad consisting of serine, histidine and aspartate. During catalysis, the serine hydroxyl acts as a nucleophile, attacking an electrophilic carbonyl carbon to generate a transient covalent acyl-enzyme intermediate. Histidine functions as a general acid-base catalyst, while aspartate stabilises the protonation state of histidine, allowing rapid turnover. Depending on reaction conditions, particularly water activity, the intermediate may undergo hydrolysis or react with an alternative nucleophile, enabling esterification or transesterification instead of bond cleavage.
Oxidoreductases employ a different catalytic strategy. Rather than forming covalent enzyme-substrate intermediates, these enzymes catalyse electron-transfer reactions using cofactors such as flavin adenine dinucleotide( FAD), nicotinamide adenine dinucleotide phosphate( NADPH), haem groups or copper centres. Peroxygenases, laccases and cytochrome P450 monooxygenases, for example, selectively oxidise plant-derived phenolics and terpenes, introducing hydroxyl groups or other oxygen-containing functionalities that would often require strong oxidants and careful reaction control using conventional chemistry.
Transferases catalyse yet another important class of transformations by transferring functional groups directly from one molecule to another. Glycosyltransferases transfer activated sugar donors to acceptor molecules, acyltransferases transfer fatty-acid groups and methyltransferases transfer methyl groups. Because the enzyme determines the orientation of both donor and acceptor, these reactions often produce a single regio- and stereoisomer, even when multiple chemically equivalent reaction sites exist.
Collectively, these catalytic mechanisms provide a molecular toolbox capable of selectively hydrolysing, functionalising, oxidising and coupling complex natural products. Rather than synthesising entirely new molecular scaffolds from simple petrochemical feedstocks, enzymes enable manufacturers to begin with the sophisticated chemical architectures already present in nature and selectively modify them to achieve the physicochemical properties required for modern cosmetic ingredients
Plant chemistry
Plants have traditionally served as sources of natural extracts for the cosmetic industry, supplying oils, botanical extracts and isolated active compounds. However, these materials represent far more than finished ingredients; they are a rich reservoir of chemical building blocks that can be selectively transformed into entirely new molecules.
Plant oils contain fatty acids that can be converted into tailored emollients and structured lipids, proteins can be hydrolysed into bioactive peptide mixtures, while polyphenols, terpenes and carbohydrates can be modified to improve properties such as solubility, stability and formulation compatibility. Rather than relying solely on extraction to recover molecules that already exist, biocatalysis enables manufacturers to redesign plant-derived materials into ingredients with physicochemical properties better suited for modern skincare formulations.
Polyphenols are attractive cosmetic scaffolds because their phenolic hydroxyl groups can support radicalscavenging activity, but those same structures may create formulation problems, including limited oil-phase compatibility and susceptibility to oxidation. Lipase-catalysed acylation can change this balance by attaching a fatty-acid chain while retaining the central aromatic scaffold.
In one recent process study, hydroxytyrosol was esterified with free fatty acids of different chain lengths using a biocatalytic system. With a 1:2 molar ratio of hydroxytyrosol to fatty acid, monoester yields reached up to 77 % after two hours. The reaction was highly selective for the primary aliphatic hydroxyl group, leaving the catechol hydroxyl groups principally responsible for antioxidant activity unmodified.
Earlier work also reported hydroxytyrosyl acetate and hydroxytyrosyl oleate esterification yields of approximately 98 % and
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