Ray Marriott

Use of green chemical technologies in an integrated biorefinery

A new concept is demonstrated for an integrated close to zero waste wheat straw biorefinery combining two novel green technologies, CO2 extraction and low temperature microwave pyrolysis, to produce a variety of products, including energy and CO2 which can be internally recycled to sustain the processes. CO2 adds value to the process by extracting secondary metabolites including fatty acids, wax esters and fatty alcohols. Low temperature microwave pyrolysis (<200 °C) is shown to use less energy and produce higher quality oils and chars than conventional pyrolysis. The oils can be fractionated to produce either transport fuels or platform chemicals such as levoglucosan and levoglucosenone. The chars are appropriate for co-firing. The quality of the chars was improved by washing to remove the majority of the potassium and chlorine present, lowering their fouling potential. The economic feasibility of a wheat straw biorefinery is enhanced by intergrating these technologies.

Biotransformation of β-myrcene to geraniol by a strain of Rhodococcus erythropolis isolated by selective enrichment from hop plants

The biocatalytic generation of high-value chemicals from abundant, cheap and renewable feedstocks is an area of great contemporary interest. A strain of Rhodococcus erythropolis designated MLT1 was isolated by selective enrichment from the soil surrounding hop plants, using the abundant triene β-myrcene from hops as a sole carbon source for growth. Resting cells of the organism were challenged with β-myrcene, and the major product of biotransformation was determined by mass spectrometric analysis to be the monoterpene alcohol geraniol. Controls demonstrated that the product was biogenic and that an aerobic environment was required. The ability to transform β-myrcene was shown to be restricted to cells that had been grown on this substrate as sole carbon source. Pre-incubation of cells with the cytochrome P450 inhibitors metyrapone or 1-aminobenzotriazole reduced geraniol production by 23% and 73% respectively, but reduction in activity was found not to correlate with the inhibitor concentration. A comparative analysis of insoluble and soluble cell extracts derived from cells of MLT1 grown on either β-myrcene or glucose revealed at least four proteins that were clearly overproduced in response to growth on β-myrcene. Mass spectrometric analysis of tryptic digests of three of these protein bands suggested their identities as an aldehyde dehydrogenase, an acyl-CoA dehydrogenase and a chaperone-like protein, each of which has a precedented role in hydrocarbon metabolism clusters in Rhodococcus sp. and which may therefore participate in a β-myrcene degradation pathway in this organism.

Enzymatic esterification of lavandulol – a partial kinetic resolution of (S)-lavandulol and preparation of optically enriched (R)-lavandulyl acetate

The asymmetric esterification of the racemic primary alcohol lavandulol was achieved using lipase B from Candida antarctica and acetic acid as acyl donor in 80% yield. The enantioselectivity of the process was characterised, and a preparative resolution of 25 mm racemic lavandulol, stopped at approx. 55% conversion, yielded (S)-lavandulol in 42% yield and 52% e.e. and (R)-lavandulyl acetate in 51% yield and 48% e.e.

Chapter 6 – CO2-based Solvents

Four classes of CO 2 -based solvents are described, with their distinctive properties and applications. Supercritical CO 2 , meaning CO 2 above its critical temperature and pressure, requires high pressure but is nontoxic, has excellent mass transfer rates and is easy to remove from products. Liquid CO 2 has many of the same benefits but at a lower temperature and pressure, although it is a particularly weak solvent. CO 2 -expanded liquids are organic liquids into which a large amount of CO 2 has been dissolved under pressure; the CO 2 content modifies and tunes many of the liquid properties. Switchable solvents can reversibly change their properties whenever needed, so that they can, for example, dissolve some material and then later release it upon application of a trigger; CO 2 at atmospheric pressure is the trigger of choice.

Triacylglycerol composition of British bluebell ( Hyacinthoides non-scripta ) seed oil

Bluebell seeds were collected from the same location for five different growth periods (2006–2010). The composition of fatty acids in the triacylglycerols present in bluebell seeds was determined using 1H- and 13C NMR and GC-MS of fatty acid methyl esters with good agreement between the different methods of analysis for the proportion of individual fatty acids. The seed oil comprised 80% ω-9 monounsaturated (C18:1, C20:1, C22:1), 10% ω-6,9 biunsaturated (C18:2) and 10% saturated fatty acids (C16:0, C18:0, C20:0, C22:0). The oil contained 25% of fatty acids with 20 or 22 carbon chain length. Gondoic acid (C20:1) was present at 20% and there was a consistency in the composition of the seed oil for the different harvest years. Based on the composition of bluebell seed oil, possible future uses are suggested and the combination of bio refining bluebell seeds in tandem with conservation efforts is proposed.