Cellulosic ethanol: interactions between cultivar and enzyme loading in wheat straw processing

<p>Abstract</p> <p>Background</p> <p>Variations in sugar yield due to genotypic qualities of feedstock are largely undescribed for pilot-scale ethanol processing. Our objectives were to compare glucose and xylose yield (conversion and total sugar yield) from straw of five winter wheat cultivars at three enzyme loadings (2.5, 5 and 10 FPU g^-1dm pretreated straw) and to compare particle size distribution of cultivars after pilot-scale hydrothermal pretreatment.</p> <p>Results</p> <p>Significant interactions between enzyme loading and cultivars show that breeding for cultivars with high sugar yields under modest enzyme loading could be warranted. At an enzyme loading of 5 FPU g^-1dm pretreated straw, a significant difference in sugar yields of 17% was found between the highest and lowest yielding cultivars. Sugar yield from separately hydrolyzed particle-size fractions of each cultivar showed that finer particles had 11% to 21% higher yields than coarse particles. The amount of coarse particles from the cultivar with lowest sugar yield was negatively correlated with sugar conversion.</p> <p>Conclusions</p> <p>We conclude that genetic differences in sugar yield and response to enzyme loading exist for wheat straw at pilot scale, depending on differences in removal of hemicellulose, accumulation of ash and particle-size distribution introduced by the pretreatment.</p

Biomass saccharification : development of strategies for enzyme recycling

In the present work the recycling of free enzymes after prehydrolysis and simultaneous saccharification and fermentation of pretreated wheat straw under a variety of conditions was investigated. It was found that a significant amount of active cellulase and glucosidase could be recovered by recycling the free cellulases the amount of free enzymes increase with its thermostability and hydrolytic efficiency. At 50° C normally regarded as an acceptable operational temperature for saccharification processes the enzymes significantly loses its activity and this thermal deactivation was independent of initial enzyme concentration used. The degree of cellulose conversion through a series of consecutive hydrolytic/recycling rounds dropped more substantially when low concentrations of cellulases were used. The hydrolysis yield and enzyme recycling efficiency in consecutive recycling rounds can be increased by using high enzyme loadings and moderate temperatures. Furthermore the recovery of cellulases from lignin lignocellulosic hydrolysates and cellulose by alkaline wash at pH 9 and 10 has been analysed

Structure and enzymatic accessibility of leaf and stem from wheat straw before and after hydrothermal pretreatment

BACKGROUND: Biomass recalcitrance is affected by a number of chemical, physical and biological factors. In this study we looked into the differences in recalcitrance between two major anatomical fractions of wheat straw biomass, leaf and stem. A set of twenty-one wheat cultivars was fractionated and illustrated the substantial variation in leaf-to-stem ratio between cultivars. The two fractions were compared in terms of chemical composition, enzymatic convertibility, cellulose crystallinity and glucan accessibility. The use of water as a probe for assessing glucan accessibility was explored using low field nuclear magnetic resonance and infrared spectroscopy in combination with hydrogen-deuterium exchange. RESULTS: Leaves were clearly more degradable by lignocellulolytic enzymes than stems, and it was demonstrated that xylose removal was more linked to glucose yield for stems than for leaves. Comparing the locations of water in leaf and stem by low field NMR and FT-IR revealed that the glucan hydroxyl groups in leaves were more accessible to water than glucan hydroxyl groups in stems. No difference in crystallinity between leaf and stem was observed using wide angle x-ray diffraction. Hydrothermal pretreatment increased the accessibility towards water in stems but not in leaves. The results in this study indicate a correlation between the accessibility of glucan to water and to enzymes. CONCLUSIONS: Enzymatic degradability of wheat straw anatomical fractions can be indicated by the accessibility of the hydroxyl groups to water. This suggests that water may be used to assess glucan accessibility in biomass samples

Rapid estimation of sugar release from winter wheat straw during bioethanol production using FTIR-photoacoustic spectroscopy

BACKGROUND: Complexity and high cost are the main limitations for high-throughput screening methods for the estimation of the sugar release from plant materials during bioethanol production. In addition, it is important that we improve our understanding of the mechanisms by which different chemical components are affecting the degradability of plant material. In this study, Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was combined with advanced chemometrics to develop calibration models predicting the amount of sugars released after pretreatment and enzymatic hydrolysis of wheat straw during bioethanol production, and the spectra were analysed to identify components associated with recalcitrance. RESULTS: A total of 1122 wheat straw samples from nine different locations in Denmark and one location in the United Kingdom, spanning a large variation in genetic material and environmental conditions during growth, were analysed. The FTIR-PAS spectra of non-pretreated wheat straw were correlated with the measured sugar release, determined by a high-throughput pretreatment and enzymatic hydrolysis (HTPH) assay. A partial least square regression (PLSR) calibration model predicting the glucose and xylose release was developed. The interpretation of the regression coefficients revealed a positive correlation between the released glucose and xylose with easily hydrolysable compounds, such as amorphous cellulose and hemicellulose. Additionally, a negative correlation with crystalline cellulose and lignin, which inhibits cellulose and hemicellulose hydrolysis, was observed. CONCLUSIONS: FTIR-PAS was used as a reliable method for the rapid estimation of sugar release during bioethanol production. The spectra revealed that lignin inhibited the hydrolysis of polysaccharides into monomers, while the crystallinity of cellulose retarded its hydrolysis into glucose. Amorphous cellulose and xylans were found to contribute significantly to the released amounts of glucose and xylose, respectively. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-015-0267-2) contains supplementary material, which is available to authorized users

Continuous recycling of enzymes during production of lignocellulosic bioethanol in demonstration scale

Recycling of enzymes in production of lignocellulosic bioethanol has been tried for more than 30 years. So far, the successes have been few and the experiments have been carried out at conditions far from those in an industrially feasible process. Here we have tested continuous enzyme recycling at demonstration scale using industrial process conditions (high dry matter content and low enzyme dosage) for a period of eight days. The experiment was performed at the Inbicon demonstration plant (Kalundborg, Denmark) capable of converting four tonnes of wheat straw per hour. 20% of the fermentation broth was recycled to the hydrolysis reactor while enzyme dosage was reduced by 5%. The results demonstrate that recycling enzymes by this method can reduce overall enzyme consumption and may also increase the ethanol concentrations in the fermentation broth. Our results further show that recycling fermentation broth also opens up the possibility of lowering the dry matter content in hydrolysis and fermentation while still maintaining high ethanol concentrations.M.O. Haven wishes to thank the Danish Agency for Science, Technology, and Innovation, grant no. 09-053694 for financial support. The other authors wish to thank the European Seventh Framework Program, grant no. 239379 (the KACELLE project) for financial support

Використання event-маркетингу в плануванні діяльності ТОВ «Микулинецький Бровар»

Акцентується увага на необхідності створення маркетингового плану для будь-якого підприємства, незалежно від форми власності та розмірів. Розглянуто сутність event - маркетингу та запропоновано event - заходи для реалізації маркетингового плану ТОВ«Мукулинецький Бровар»Accentuates the need to create a marketing plan for any enterprise, regardless of firm size. The essence of event - and proposed marketing event - measures to implement a marketing plan Ltd. Mukulynetskyy Brova