The purpose of this review is to give the reader a thorough background to the fundamentals and applications of pressurized hot water extraction (PHWE) for the analysis of bioactive compounds. We summarize the field in the period 2009–14, and include fundamentals of water as a solvent: equipment; method optimization; applications; coupling; and, future prospects. We highlight that solvent properties of water are tunable by changing the temperature, particularly self-ionization, dielectric constant, viscosity, diffusivity, density and surface tension. Furthermore, important aspects to consider are the risk of degradation of the analytes and other potential reactions, such as hydrolysis, caramelization and Maillard reactions that may lead to erroneous results. For the extraction of bioactive compounds, we report PHWE methods based on using water of 80–175°C and short extraction times. In conclusion, PHWE provides advantages over conventional extraction methods, such as being “greener”, faster and more efficient

Lignin is a major component of lignocellulosic biomass and as such, it is processed in enormous amounts in the pulp and paper industry worldwide. In such industry it mainly serves the purpose of a fuel to provide process steam and electricity, and to a minor extent to provide low grade heat for external purposes. Also from other biorefinery concepts, including 2nd generation ethanol, increasing amounts of lignin will be generated. Other uses for lignin - apart from fuel production - are of increasing interest not least in these new biorefinery concepts. These new uses can broadly be divided into application of the polymer as such, native or modified, or the use of lignin as a feedstock for the production of chemicals. The present review focuses on the latter and in particular the advances in the biological routes for chemicals production from lignin. Such a biological route will likely involve an initial depolymerization, which is followed by biological conversion of the obtained smaller lignin fragments. The conversion can be either a short catalytic conversion into desired chemicals, or a longer metabolic conversion. In this review, we give a brief summary of sources of lignin, methods of depolymerization, biological pathways for conversion of the lignin monomers and the analytical tools necessary for characterizing and evaluating key lignin attributes.

The seed oil derived from the tung (Aleurites fordiiHemsl.) tree contains approximately 80% α-eleostearic acid (18:3Δ^{9cis,11trans,13trans}), an unusual conjugated fatty acid that imparts industrially important drying qualities to tung oil. Here, we describe the cloning and functional analysis of two closely related Δ¹² oleate desaturase-like enzymes that constitute consecutive steps in the biosynthetic pathway of eleostearic acid. Polymerase chain reaction screening of a tung seed cDNA library using degenerate oligonucleotide primers resulted in identification of two desaturases, FAD2 and FADX, that shared 73% amino acid identity. Both enzymes were localized to the endoplasmic reticulum of tobacco (Nicotiana tabacumcv Bright-Yellow 2) cells, and reverse transcriptase-polymerase chain reaction revealed that FADX was expressed exclusively within developing tung seeds. Expression of the cDNAs encoding these enzymes in yeast (Saccharomyces cerevisiae) revealed that FAD2 converted oleic acid (18:1Δ^9cis) into linoleic acid (18:2Δ^9cis,12cis) and that FADX converted linoleic acid into α-eleostearic acid. Additional characterization revealed that FADX exhibited remarkable enzymatic plasticity, capable of generating a variety of alternative conjugated and Δ¹²-desaturated fatty acid products in yeast cells cultured in the presence of exogenously supplied fatty acid substrates. Unlike other desaturases reported to date, the double bond introduced by FADX during fatty acid desaturation was in the trans, rather than cis, configuration. Phylogenetic analysis revealed that tung FADX is grouped with Δ¹² fatty acid desaturases and hydroxylases rather than conjugases, which is consistent with its desaturase activity. Comparison of FADX and other lipid-modifying enzymes (desaturase, hydroxylase, epoxygenase, acetylenase, and conjugase) revealed several amino acid positions near the active site that may be important determinants of enzymatic activity.