Exploring the Photocatalytic Cleavage Pathway of the β-5 Linkage Lignin Model Compound on Carbon Nitride.

As a globally abundant source of biomass, lignocellulosic biomass has been the centre of attention as a potential resource for green energy generation and value-added chemical production. A key component of lignocellulosic biomass, lignin, which is comprised of aromatic monomers, is a potential feedstock for value added chemical production. The cleavage processes of the linkages between monomers to obtain high value products, however, requires significant investigation as it is a complex, non-facile process.

Temporal patterns of fucoxanthin in four species of European marine brown macroalgae.

Brown seaweeds are a rich source of carotenoids, particularly fucoxanthin, which has a wide range of potential health applications. Fucoxanthin fluctuates within and among seaweeds over time, frustrating efforts to utilise this resource. Thus, we require comprehensive analyses of long- and short-term concentrations across species in field conditions.

Ruthenium ion catalysed C-C bond activation in lignin model compounds - towards lignin depolymerisation.

Lignin is the most abundant renewable feedstock to produce aromatic chemicals, however its depolymerisation involves the breaking of several C-O and C-C inter-unit linkages that connect smaller aromatic units that are present in lignin. Several strategies have been reported for the cleavage of the C-O inter-unit linkages in lignin. However, till today, only a few methodologies have been reported for the effective breaking or the conversion of the recalcitrant C-C inter unit linkages in lignin.

Photocatalytic Reforming of Biomass: What Role Will the Technology Play in Future Energy Systems.

Photocatalytic reforming of biomass has emerged as an area of significant interest within the last decade. The number of papers published in the literature has been steadily increasing with keywords such as 'hydrogen' and 'visible' becoming prominent research topics. There are likely two primary drivers behind this, the first of which is that biomass represents a more sustainable photocatalytic feedstock for reforming to value-added products and energy.

Polyphenols from Brown Seaweeds as a Potential Antimicrobial Agent in Animal Feeds.

Seaweeds offer a natural source of antimicrobials that may help curb antibiotic resistance in livestock. The antibacterial activity of phlorotannin extracts isolated from two brown seaweeds and was tested. The mechanism of action of phlorotannin extracts against O157, , and was elucidated by observing cell membrane permeability and intracellular adenosine triphosphate (ATP).

A critical review of analytical methods used for the chemical characterisation and quantification of phlorotannin compounds in brown seaweeds.

Introduction: Phlorotannins, the phenolic compounds found in brown seaweeds, are a unique and diverse class of compounds showing a huge potential for food and pharmaceutical applications.

Objective: This review will give an account of the colorimetric assays used and a discussion of their quantitative and qualitative analytical shortcomings. It will also discuss other more complex and modern analytical chemistry methods that are currently being developed to study phlorotannins.

A chemoenzymatic synthesis of 5a-carba-α-D-mannose-6-phosphate.

An efficient chemical synthesis of 5a-carba-α-D-mannose and its enzymatic elaboration to 5a-carba-α-D-mannose-6-phosphate, using yeast hexokinase, is described.

Dioxygenase-catalysed oxidation of disubstituted benzene substrates: benzylic monohydroxylation versus aryl cis-dihydroxylation and the meta effect.

Biotransformations of a series of ortho-, meta- and para-substituted ethylbenzene and propylbenzene substrates have been carried out, using Pseudomonas putida UV4, a source of toluene dioxygenase (TDO). The ortho- and para-substituted alkylbenzene substrates yielded, exclusively, the corresponding enantiopure cis-dihydrodiols of the same absolute configuration. However, the meta isomers, generally, gave benzylic alcohol bioproducts, in addition to the cis-dihydrodiols (the meta effect).

Biotransformation of substituted pyridines with dioxygenase-containing microorganisms.

A series of 2-, 3- and 4-substituted pyridines was metabolised using the mutant soil bacterium Pseudomonas putida UV4 which contains a toluene dioxygenase (TDO) enzyme. The regioselectivity of the biotransformation in each case was determined by the position of the substituent. 4-Alkylpyridines were hydroxylated exclusively on the ring to give the corresponding 4-substituted 3-hydroxypyridines, while 3-alkylpyridines were hydroxylated stereoselectively on C-1 of the alkyl group with no evidence of ring hydroxylation.

Selective opening of ring C in the morphine skeleton by an unexpected cleavage of the C5-C6 bond in cycloadducts of thebaine and acyl nitroso compounds.

[reaction: see text] Acyl nitroso cycloadducts of the alkaloid thebaine undergo an unexpected cleavage of the C5-C6 bond when treated with 2 equiv of samarium(II) iodide in THF to give novel hexahydrobenzazocine products. A proposed mechanism for the transformation involves rearrangement of the initial radical anion.