Barley Straw Residues Research Articles

Lignin-enriched residues from bioethanol production: Chemical characterization, isocyanate functionalization and oil structuring properties

Lignin-enriched waste products from bioethanol production of agriculture residues were tested as structuring agents in castor oil once functionalized with hexamethylene diisocyanate. Cane bagasse, barley and wheat straw were processed through steam explosion, pre-saccharification and simultaneous saccharification and fermentation (PSSF). Alternatively, cane bagasse was submitted to steam explosion and enzymatic hydrolysis (EH). Several Nuclear Magnetic Resonance techniques were used to characterize both residues and NCO-functionalized counterparts. The β-O-4′/resinol/phenylcoumaran content and hydroxyphenyl/guaiacyl/syringyl distribution depend on biomass source, pretreatment, and enzymatic hydrolysis. Total hydroxyl content (from 1.23 for cane bagasse to 1.85 for wheat straw residues), aromatic/aliphatic hydroxyl ratio (0.78 for cane bagasse and 0.61 and 0.49 for barley and wheat straw residues, respectively) and S/G ratio (ranging from 0.25 to 0.86) influence the NCO-functionalization and oleogel rheological response. Oleogels obtained with barley straw residues exhibited the highest values of the storage modulus; around 2 × 105 Pa and 104 Pa for 25% and 20% contents, respectively. PSSF process showed weaker modification, leading to softer viscoelastic response compared to EH. These oleogels exhibited rheological properties similar to lubricating greases of different NLGI grades. Therefore, we herein show an integrative protocol for the valorization of lignin-enriched residues from bioethanol production as potential thickeners of lubricating greases.

Cellulose Pulp- and Castor Oil-Based Polyurethanes for Lubricating Applications: Influence of Streptomyces Action on Barley and Wheat Straws.

The replacement of mineral oils and non-renewable gelling agents is an imperative requirement for the lubricant industry in the near future. In this framework, cellulose pulp and castor oil are proposed as sustainable substitutes for these components. Biological treatment has been explored and evaluated to enhance the dispersing and thickening properties of cellulose pulp in oil media. Streptomyces sp. MDG147 and MDG301 strains were employed to modify agricultural wheat and barley straw residues from which cellulose pulp was obtained afterwards. In addition, an environmentally friendly process for the production of cellulose-pulp-/castor-oil-based polyurethanes was applied, in which neither catalysts nor harmful solvents were used, resulting in chemical oleogels. These oleogels were rheologically and tribologically characterized to evaluate their performance as lubricating greases. The enzymatic activity pattern developed was dependent on the raw material, the strain type, and the temperature, influencing the cellulose pulp’s composition, polymerization degree, and crystallinity. These modified characteristics tuned the rheological behavior of the different oleogels, providing a beneficial range of viscoelastic responses and viscosity values that were generally favored by the Streptomyces action. Furthermore, the friction coefficient and dimensions of wear scars measured in a tribological contact were comparable to, or even lower than, those found with commercial and other bio-based lubricating greases that have previously been studied.

Feasibility of Barley Straw Fibers as Reinforcement in Fully Biobased Polyethylene Composites: Macro and Micro Mechanics of the Flexural Strength.

Awareness on deforestation, forest degradation, and its impact on biodiversity and global warming, is giving rise to the use of alternative fiber sources in replacement of wood feedstock for some applications such as composite materials and energy production. In this category, barley straw is an important agricultural crop, due to its abundance and availability. In the current investigation, the residue was submitted to thermomechanical process for fiber extraction and individualization. The high content of holocellulose combined with their relatively high aspect ratio inspires the potential use of these fibers as reinforcement in plastic composites. Therefore, fully biobased composites were fabricated using barley fibers and a biobased polyethylene (BioPE) as polymer matrix. BioPE is completely biobased and 100% recyclable. As for material performance, the flexural properties of the materials were studied. A good dispersion of the reinforcement inside the plastic was achieved contributing to the elevate increments in the flexural strength. At a 45 wt.% of reinforcement, an increment in the flexural strength of about 147% was attained. The mean contribution of the fibers to the flexural strength was assessed by means of a fiber flexural strength factor, reaching a value of 91.4. The micromechanical analysis allowed the prediction of the intrinsic flexural strength of the fibers, arriving up to around 700 MPa, and coupling factors between 0.18 and 0.19, which are in line with other natural fiber composites. Overall, the investigation brightness on the potential use of barley straw residues as reinforcement in fully biobased polymer composites.

Use of barley straw residues to avoid high erosion and runoff rates on persimmon plantations in Eastern Spain under low frequency–high magnitude simulated rainfall events

Soil and water losses due to agricultural mismanagement are high and non-sustainable in many orchards. An experiment was set up with rainfall simulation at 78 mm h–1 over 1 hour on 20 paired plots of 2 m2 (bare and straw covered) in new persimmon plantations in Eastern Spain. Effects of straw cover on the control of soil and water losses were assessed. An addition of 60% straw cover (75 g m–2) resulted in delayed ponding and runoff generation and consequently reduced water losses from 60% to 13% of total rainfall. The straw cover reduced raindrop impact and thus sediment detachment from 1014 to 47 g plot–1 h–1. The erosion rate was reduced from 5.1 to 0.2 Mg ha–1 h–1. The straw mulch was found to be extremely efficient in reducing soil erosion rates.

Genes Involved in Cyclic Lipopeptide Production Are Important for Seed and Straw Colonization byPseudomonassp. Strain DSS73

Survival in natural bulk soil and colonization of sugar beet seeds and barley straw residues were determined for Pseudomonas sp. strain DSS73 and Tn5 mutants in amsY (encoding a peptide synthetase involved in production of the cyclic lipopeptide amphisin) and gacS (encoding the sensory kinase of the two-component GacA/GacS regulatory system). No differences in survival or growth in response to carbon amendment (citrate) were observed in bulk soil. However, both mutants were impaired in their colonization of sugar beet seeds and barley straw residues by an inoculum established in the bulk soil. The two mutants had comparable colonization phenotypes, suggesting that amphisin production is more important for colonization than other gacS-controlled traits.

The sexed shape of Helminthosporium gramineum Rabh. fungus involved in increasing disease damage of torn leaves in barley

The onset of some sclerotic formations are reported on barley straws on which the following microscopic investigations and biometrical measurements peritecia, ascia and ascospores of Pyrenophora graminea (Rabh. Ito et Kurib.) were detected, representing the sexed multiplication of fungus Helminthosporium gramineum , the pathogenic factor causing leaf tearing in barley, a condition rarely encountered in nature. Owing to the great number of peritecia on barley straw residues, we are of the opinion that the sexed multiplication of fungus represents a real danger in barley cultivation assigning the efficient control steps against this pest.

Microbially corrected amino acid composition of rumen-undegraded feed protein and amino acid degradability in the rumen of feeds enclosed in nylon bags.

1. In the previous work (Varvikko & Lindberg, 1985), 15N-labelled rapeseed (Brassica napus), barley, ryegrass (Lolium perenne) and barley straw were incubated in the rumen in nylon bags for 5, 12 and 24 h and microbial nitrogen in the residues was quantified using the feed 15N-dilution method. In the present study, residual amino acids (AA) of these feeds were analysed, and microbially corrected AA of feed origin (feed AA) were estimated as the difference between total residual AA and respective microbial AA, assuming a constant AA composition for the microbial protein. 2. In barley and barley-straw residues, and also in ryegrass incubated in the rumen for 24 h, very large enrichment by microbial N and AA-N was found. The microbial enrichment was rather small in rapeseed residues and ryegrass incubated for 5 or 12 h. During the rumen incubation, feed N and AA-N (g/kg feed dry matter (DM] decreased very clearly in all the feeds, and feed and incubation time effects were always statistically significant (P less than 0.001). 3. The slow degradation of essential (E) feed AA compared with the respective non-essential (NE) AA degradation increased the proportion of feed EAA (g/kg determined feed AA) in barley and barley-straw residues. In rapeseed and ryegrass, residual feed EAA:NEAA remained very similar to the original. Branched-chain (Br) AA tended to increase proportionally in all the feed residues, suggesting these AA to be, on average, more resistant against microbial degradation in the rumen than other AA. Similarly, lysine was clearly increased in barley residues. A rumen degradation faster than the average rate caused decreased residual feed glutamic acid in rapeseed; methionine, alanine and glycine in barley; arginine and alanine in ryegrass; and methionine, asparagine and tyrosine in barley straw. Feed and incubation time effects were significant (P less than 0.05-0.001) for feed AA (g/kg determined feed AA) grouped as EAA, BrAA or NEAA, and for most individual AA, as well as for feed AA disappearance (%) and relative amounts (%) of feed AA in the respective residual AA. 4. According to present findings, AA composition of the rumen-degraded vegetable feed residues may markedly differ, either quantitatively or qualitatively (or both), from their original AA composition. When determining the feed AA composition of nylon-bag residues, the microbial error may be very large with starchy or fibrous feeds of low protein content. The microbial AA do not, however, considerably confuse the AA determination of protein-rich feeds.

Septoria passerinii . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Septoria passerinii . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Hordeum brachyantherum, Hordeum distichon, Hordeum jubatum, Hordeum secalinum, Hordeum vulgare, Hystrix patula, Lolium multiflorum, L. perenne, L. temulentum, Poa pratensis and Sitanion hystrix . DISEASE: Speckled leaf blotch of barley. Forming linear lesions with indefinite margins on leaves with very small, dark brown pycnidia embedded in tissues developing on straw-coloured blotches and causing defoliation, low yields and formation of light kernels. GEOGRAPHICAL DISTRIBUTION: Africa (Ethiopia, Libya); Australasia & Oceania (Australia); Europe (Bulgaria, Cyprus, Denmark, Germany, Italy, Netherlands, Rumania, Spain, U.K.); North America (Canada, U.S.A.). TRANSMISSION: The pathogen overwinters as mycelium or as pycnidia in crop residues, producing macrospores and microspores the following summer. High humidity (>93% R.H.) is required for the release of spores which are formed abundantly on infected material after rain. Spores may be spread by insects or splashing raindrops (44, 1528; 46, 106; 40: 530). Dissemination of the pathogen on barley straw residues has also been attributed to the use of combine harvester-threshers in Western Canada (35: 418) and to high winds in Minnesota, U.S.A. (40: 530).