Wheat straw phenols

Key words xylose-rich pectic polysaccharide, pectin, wheat straw, extraction, sugars, lignin, FT-IR, phenolic acids and aldehydes. 

Reversed-phase chromatography is the most popular mode of analytical liquid chromatography for phenolic compounds. In most cases, the reported systems for the separation of phenolics and their glycosides in foods are carried out on reversed-phase chromatography on silica-based Cl8 bonded-phase columns. Occasionally, silica columns bonded with C8 were applied in the analysis of phenolic acid standards and coumarins (7), and C6 columns for the analysis of ferulic acid in wheat straw (8). 

Martin, J. P. and Haider, K., 1979. Effect of concentration on decomposition of some 14C-labeled phenolic compounds, benzoic acid, glucose, cellulose, wheat straw, and Chlorella protein in soil. Soil Sci. Soc. Amer. J. 43, 917-920... 

Scalbert A, Monties B, Lallemand J Y, Guittet E, Roland C (1985) Ether linkages between phenolic acids and lignin fractions from wheat straw Phytochemistry 24 1359- 1362... 

Current research indicates that there is a growing interest in natural fibers. Natural fibers Ifom jute were tested in thermosetting and thermoplastic resins. Lignin fillers were used in phenol-formaldehyde, SBR, SBS, and S1S ° and with good results. The opportunities for applications of natural fibers in industrial products have been the subject of recent reviews. Cellulose whiskers with a high reinforcing value were obtained from wheat straw. " Wood fibers were found applicable to such diverse materials as polypropylene... 

A Scalbert, B Monties, J-Y LaUemand, E Guittet, C Rolando. Ether linkage between phenolic acids and lignin fractions from wheat straw. Phytochemistry 24 1359-1362, 1985. 

However, there has been some interesting work in the USA on soybean, as a potential source of TS binder resins. These resins are being developed by the United Soybean Board, St Louis, Missouri, USA, under the name Proteinol. They are made from various waste cellulosic fibers tightly bound with various soy protein/phenolic binder systems. Fillers can be agricultural crop wastes such as wheat straw, corn, bagasse, kenaf, or hemp, forest waste products such as wood fibers, shavings, sawdust or chips, and shredded newsprint, de-inked office paper, and other recycled products. Extruded and compression molded shapes are being produced, which can be nailed, drilled, sawn, routed, sanded, painted and stained. 

Phenol-formaldehyde resins are among the most important polymeric adhesives used in the wood based composite panel manufacturing industries [1]. Phenolic resins are prepared by the reaction of phenol or any substituted phenol with formaldehyde or other aldehydes, in the presence of acidic or basic catalyst. The price of phenol depends on the oil price and is likely to ever increase due to shortage of fossil resources. Hence, several lignin substitute products based on renewable materials derived from annual plants such as flax [2, 3] or kenaf [4], agricultural waste such as sugar cane bagasse [5] and wheat straw [6] or by-products from the... 

The composition and concentration of the inhibitors are dependent on the biomass substrate, pre-treatment method and pre-treatment condition. Tomas-Pejo et al. reported that in a steam explosion pre-treated wheat straw hydrolysate, furfural, HMF, acetic acid, formic acid and ferulic acid were detected with concentrations of 1.4, 0.1, 5.1, 1.3 and <0.1 g L , respectively. Figure 6.4 summarizes the common inhibitor concentrations based on the data reported in two recent review papers. The furfural concentration was found to be in the range of 0.15 to 2.2 g L , while the HMF was generally lower than 1 g except for spruce-derived hydrolysates. Acetic acid and formic acid concentrations were around 1.6 to 5.5 g and 0.7 to 3.1 g L, respectively. Phenolics had a wide spread from 0.1 to 4.5 g L , depending on the pre-treatment and detection methods. Only few publications reported levulinic acid inhibitor, which is mainly from woody biomass. 

Fig. 3.8 Phenolic acids extracted from wheat stubble, wheat straw from half buried litter bags, and wheat stubble/soybean (no-till) soil. Phenolic acids isolated and quantified were caffeic acid (CAF), ferulic acid (FER), p-coumaric acid (PCO), p-hydroxybenzoic acid (POH), sinapic acid (SIN), syringic acid (SYR), and vanillic acid (VAN). Becausep-coumaric acid was so high in comparison to other phenolic acids in wheat residues, data are presented twice, once with p-coumaric acid (a) and once without p-coumaric acid (b). Because phenolic acids were so low in the soil they are also presented in (c). The absence of standard error bars for wheat straw and soil indicates that the error bars are too small to be visible. Figures based on data from Blum et al. (1991, 1992). Plenum Publishing Corporation, data used with permission of Springer Science and Business Media...

Mean concentrations of available individual benzoic and cinnamic acid derivatives determined in this Cecil soil were small, less than 4 xg/g soil. The sums of 7 individual phenolic acids (0-2.5 cm soil cores) for wheat stubble tilled under/soybean and fallow/soybean soil samples were 58 and 38%, respectively, of wheat stub-ble/soybean soil samples (100% =12.30 0.58 tig/g). The sum of 7 individual phenolic acids for the 0-2.5 cm core samples was approximately 34% higher than for the 0-10 cm core samples. Plant tissues/residues contained greater individual phenolic acid content than soils. For example wheat stubble contained 258 times and wheat straw from half buried litter bags 65 times the p-coumaric acid of wheat no-till Cecil A soils (4 tig/g soil). 

Mortierella isabellina could grow on both C5 (arabinose, ribose, xylose, and mannose) and disaccharides (sucrose and cellobiose). When grown in the presence of model lignocellulosic inhibitor compounds, phenolic compounds were highly inhibitory, while furfural, 5-HMF, acetic acid, formic acid, and levulinic acid showed limited inhibition. Surprisingly acetic and formic acid improved lipid production by twofold as compared with that observed for the control. When grown on wheat straw, hydrolysate up to 53 % total lipids was obtained with a lipid yield of 16.8 % from the carbon sources (Zeng et al. 2013). 

Tabarsa, T, Jahanshahi, S., and Ashori, A. (2011). Mechanical and physical properties of wheat straw boards bonded with a tannin modified phenol-formaldehyde adhesive. Composites Part B Eng., 42(2), 176-180. doi 10.1016/j.compositesb.2010.09.012. 

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