Analysis of lignin degradation products by capillary electrophoresis

The chemical logic of enzymatic lignin degradation

Lignin is an aromatic heteropolymer, found in plant cell walls as 20-30% of lignocellulose. It represents the most abundant source of renewable aromatic carbon in the biosphere, hence, if it could be depolymerised efficiently, then it would be a highly valuable source of renewable aromatic chemicals. However, lignin presents a number of difficulties for biocatalytic or chemocatalytic breakdown. Research over the last 10 years has led to the identification of new bacterial enzymes for lignin degradation, and the use of metabolic engineering to generate useful bioproducts from microbial lignin degradation. The aim of this article is to discuss the chemical mechanisms used by lignin-degrading enzymes and microbes to break down lignin, and to describe current methods for generating aromatic bioproducts from lignin using enzymes and engineered microbes.

Challenges and opportunities of hydrothermal carbonisation in the UK; case study in Chirnside

The latest research and development in hydrothermal carbonisation (HTC) processes are reviewed and the feasibility of application to small towns in the UK is assessed. The HTC process designed in this report is theoretically evaluated for the biodegradable municipal waste and sewage waste produced by the small town of Chirnside, in the Scottish Borders. Calculation of mass and energy balances of the process are carried out alongside the evaluation of challenges and environmental, social and economic opportunities presented. The hypothetical HTC plant is capable of processing 267.14 t per year of food waste and 105.12 t per year of faecal sludge produced by Chirnsides estimated 2250 residents in 2041. The plant would be capable of producing 99.08 t per year of hydrochar with an estimated total energy content of 540.26 MWh per year. When used in a Biomass Combined Heat and Power Plant, the hydrochar would be capable of supplying Chirnsides residents with 0.71% and 3.43% of its domestic thermal energy demand and domestic electrical energy demand in 2041, respectively. Both the expected opportunities and challenges for the application of HTC are discussed, shedding light on the associated research in regards to this sustainable technology.

The latest research and development in hydrothermal carbonisation (HTC) processes are reviewed and the feasibility of application to small towns in the UK is assessed.

Challenges and opportunities of hydrothermal carbonisation in the UK; case study in Chirnside

Hydrothermal carbonization: a great technology converting biomass waste to energy.

Use of earthworms (Eisenia fetida) to reduce phytotoxicity and promote humification of pre-composted olive oil mill wastewater

BACKGROUND

Olive mill wastewaters (OMWW) contain a high recalcitrant organic load and an associated toxicity that make their treatment necessary before environmental application. The aim of this study was to evaluate the feasibility of promoting the valorization and reducing the phytotoxicity of OMWW through a pre-composting process together with straw-chip bulking materials followed by the application of earthworms (Eisenia fetida) in the presence of oat seedlings (Avena sativa L.) seedlings.

RESULTS

After 3 months, the pre-composted material showed properties similar to a partially digested compost with some significant amelioration of chemical-physical and biochemical properties. The application of earthworms permitted a significant decrease in chemical (total organic carbon, water-extractable organic carbon, total nitrogen) and biological parameters (dehydrogenase enzyme activity), and an increase in humic substances and available nitrogen forms. In the presence of plants a higher C/N ratio and a lower content of nitrates were observed. In addition, the reduction in phenolic compounds observed in treatments with earthworms caused a decrease in phytotoxicity by about 50% with respect to the pre-composted material, which results in an increase in germination index.

CONCLUSION

The utilization of earthworms, in particular in the presence of plants, may be an ecologically sound and economically feasible technology to obtain a non-toxic, high-value product useful for agricultural purposes.

EXAFS structural analysis of aqueous uranium(VI) complexes with lignin degradation products

Uranium LIII-edge extended X-ray absorption fine structure (EXAFS) analysis was carried out on aqueous uranium(VI) complexes with monomeric intermediates of the natural wood-degradation process such as protocatechuic acid (3,4-dihydroxybenzoic acid), catechol (2-hydroxyphenol), pyrogallol (1,2,3-trihydroxybenzol), and vanillic acid (4-hydroxy-3-methoxybenzoic acid). The structural parameters of the 1:1 complexes with protocatechuic acid and vanillic acid in weakly acidic solution indicate that the carboxylic group coordinates the uranyl cation in a bidentate mode in the equatorial plane. Based on the identical structural parameters observed for protocatechuic acid, catechol and pyrogallol in alkaline media, we conclude that the coordination with uranium occurs via the neighboring OH groups of the phenols under formation of a five-membered ring.

Structure Design of Multifunctional Furoate and Pyroglutamate Esters of Dextran by Polymer-Analogous Reactions

Well-defined multifunctionalized dextran esters bearing photo-crosslinkable and chiral groups as well as small alkyl moieties for the adjustment of the solubility were prepared from two dextran samples with different origin and molecular weight. The examination of side structures of the starting dextran was carried out by different one- and two-dimensional NMR techniques. The main synthesis path via in situ activation of furan-2-carboxylic- and pyroglutamic acid with CDI under mild conditions gives highly functionalized dextran derivatives possessing a degree of polymerization in the range of the starting polysaccharide. The subsequent reaction with propionic anhydride leads to completely substituted, CHCl(3) soluble derivatives useful for the determination of the particular degree of substitution. By variation of the molar ratios of polymer to reagent with photo-crosslinkable- and chiral moieties during the reaction and even by subsequent peracylation, multifunctional dextran derivatives with adjustable properties like the hydrophilic/hydrophobic balance were obtained that may form biocompatible spherical nanoparticles.