Regioselective thexyldimethylsilylation of (1➔3)-glucans - Does the linkage type matter.

α- and β-(1➔3)-linked polysaccharides dissolved in N,N-dimethyl acetamide (DMA) were subjected to conversion with thexyldimethylchlorosilane (TDMS-Cl) in presence of pyridine as base. A degree of substitution of TDMS groups (DS) between 0.7 and 1.

A chemo-enzymatic pathway to expand cellooligosaccharide chemical space through amine bond introduction.

Enzymatic functionalization of oligosaccharides is a useful and environmentally friendly way to expand their structural chemical space and access to a wider range of applications in the health, food, feed, cosmetics and other sectors. In this work, we first tested the laccase/TEMPO system to generate oxidized forms of cellobiose and methyl β-D-cellobiose, and obtained high yields of novel anionic disaccharides (>60 %) at pH 6.0.

Bacterial α-Glucan and Branching Sucrases from GH70 Family: Discovery, Structure-Function Relationship Studies and Engineering.

Glucansucrases and branching sucrases are classified in the family 70 of glycoside hydrolases. They are produced by lactic acid bacteria occupying very diverse ecological niches (soil, buccal cavity, sourdough, intestine, dairy products, etc.).

Natural and engineered transglycosylases: Green tools for the enzyme-based synthesis of glycoproducts.

An increasing number of transglycosylase-based processes provide access to oligosaccharides or glycoconjugates, some of them reaching performance levels compatible with industrial developments. Nevertheless, the full potential of transglycosylases has not been explored because of the challenges in transforming a glycoside hydrolase into an efficient transglycosylase. Advances in studying enzyme structure/function relationships, screening enzyme activity, and generating synthetic libraries guided by computational protein design or machine learning methods should considerably accelerate the development of these catalysts.

Characterization of the First α-(1→3) Branching Sucrases of the GH70 Family.

Leuconostoc citreumNRRL B-742 has been known for years to produce a highly α-(1→3)-branched dextran for which the synthesis had never been elucidated. In this work a gene coding for a putative α-transglucosylase of the GH70 family was identified in the reported genome of this bacteria and functionally characterized. From sucrose alone, the corresponding recombinant protein, named BRS-B, mainly catalyzed sucrose hydrolysis and leucrose synthesis.

Selection of CalB immobilization method to be used in continuous oil transesterification: analysis of the economical impact.

Enzymatic transesterification of triglycerides in a continuous way is always a great challenge with a large field of applications for biodiesel, bio-lubricant, bio-surfactant, etc. productions. The lipase B from Candida antarctica (CalB) is the most appreciated enzyme because of its high activity and its non-regio-selectivity toward positions of fatty acid residues on glycerol backbone of triglycerides.

Continuous lipase-catalyzed production of esters from crude high-oleic sunflower oil.

The objective of this work was to develop an economically relevant enzymatic process of butyl ester production using crude high-oleic sunflower oil. Novozym 435, a non-regiospecific biocatalyst, provided the best compromise between activity and butyl-ester yield. The inhibition caused by the presence of phopholipids in crude oil was eliminated by using tert-butanol.