Increase In Sugar Yield Research Articles

Disruption of lignocellulosic biomass along the length of the screws with different screw elements in a twin-screw extruder

Proper screw design is crucial for effectively pre-treating wood fibers, to assist in the downstream enzymatic conversion of the cellulose into fermentable sugars. Initially, the impact of extruder barrel temperature (50, 100, and 150 °C) and screw speed (25, 50, and 75 rpm) were studied to arrive at the optimum conditions for sugar yield. Lower temperatures and screw speeds resulted in increased sugar yields. To examine the influence of shear imparted by the screws, the residuals samples were recovered from different zones along the screws and evaluated. Sugar yield, crystallinity index, and the particle size distribution of the material collected at different zones were determined. Glucose yield and xylose/mannose yields of the material along the screws, ranged from 23.25 to 42.88% and from 11.95 to 20.54%, respectively. The importance of the screw design was highlighted.

Influence of soil characteristics on yield response to lime in sugar beet

Sugar beet is an economically important crop grown on around 30,000 ha in the province of Skåne in the south of Sweden. This project examined the effects of lime on soil factors and yield response in sugar beet in 52 soils in Skåne. Previous research in sugar beet in this area has postulated the importance of appropriate calcium concentrations in the soil to avoid yield losses caused by the root pathogen Aphanomyces cochlioides. Field trials on liming in Sweden have, however shown contrasting results on yield and subsequent economic benefits. The practice of liming has therefore been neglected and resulted in suboptimal pH for plant growth and development in many soils. The aim of the present investigation was to identify and evaluate soil factors of importance for a positive yield response in sugar beet after application of two different lime products: factory lime and limestone meal in rates with similar neutralizing effect (4 tons CaO/ha). Data on soil texture, cation exchange capacity (CEC) and clay mineralogy were available for each site. After liming, nutritional status and Aphanomyces root rot potential in the soil were analysed in each treatment and finally the yield was measured. In total, 52 soils were treated with the two lime products. In addition, 12 of these were also treated with increasing doses of limestone meal.In average for all 52 soils, the yield increased significantly after treatment with either of the lime products. Similarly, the root rot potential of A. cochlioides decreased significantly with no difference between the products. In 12 field trials with 4, 8, 16 and 32 ton/ha limestone meal, 8 ton/ha gave the highest yield. In classifying the soils according to pH and prevailing recommendations, soils with an initial pH >7.0 and with no liming requirement responded positively with significant increases in sugar yield. Soils with initial pH 6.5–7.0 and with a liming requirement, showed less response, with no significant increase in sugar yield. However, the concentration of calcium increased above the suggested threshold of 250 mg/100 g soil and the root rot potential of A. cochlioides decreased significantly in this group. For soils with an initial pH <6.5, the calcium content remained unchanged after liming. Also, Aphanomyces root rot, which was most prevalent in these soils, was not affected by liming. These soils have a low buffering capacity due to the combined effects of clay mineralogy with a low proportion swelling clay minerals and a low clay content. Sugar beets have been shown to acidify the rhizosphere and a high buffering capacity and a high base saturation maintain an optimal pH for nutrient uptake. The results suggest that for crop rotations including sugar beet, liming should be done on a regular basis, also for soils with a pH >7.0. It is of special importance in soils with low pH and CEC to maintain or increase calcium concentrations to a level >250 mg/100 g, which reduce the propagation of A. cochlioides.

Application of ionic liquid and alkali pretreatment for enhancing saccharification of sunflower stalk biomass for potential biofuel-ethanol production

Biorefining of lignocellulosic biomass to fuels/chemicals has recently gained immense research momentum. Current study reports sequential pretreatment of sunflower stalk (SFS) biomass in a combinatorial regime involving alkali (NaOH) and ionic liquid 1-butyl-3-methyl imidazolium chloride. The pretreatment enhanced the enzymatic digestibility, and resulted in increased sugar yield (163.42 mg/g biomass) as compared to standalone pretreatment using alkali (97.38 mg/g biomass) or ionic liquid (79.6 mg/g biomass). Ultrastructural and morphological analysis (FTIR and SEM) of pretreated biomass showed that the combined ionic liquid and alkali pretreatment causes more drastic alterations in the biomass ultrastructure as compared to alone ionic liquid or alkali pretreatment. Thus, combined pretreatment led to ease of enzymatic saccharification and consequent increased sugar yield, and this observation was corroborated by physicochemical analysis of the pretreated biomass. The pretreated SFS biomass was subjected to consolidated bioprocessing for its direct conversion to bioethanol in a single vessel.

Dynamic modeling of subcellular phenylpropanoid metabolism in Arabidopsis lignifying cells

Lignin is a polymer that significantly inhibits saccharification of plant feedstocks. Adjusting the composition or reducing the total lignin content have both been demonstrated to result in an increase in sugar yield from biomass. However, because lignin is essential for plant growth, it cannot be manipulated with impunity. Thus, it is important to understand the control of carbon flux towards lignin biosynthesis such that optimal modifications to it can be made precisely. Phenylalanine (Phe) is the common precursor for all lignin subunits and it is commonly accepted that all biosynthetic steps, spanning multiple subcellular compartments, are known, yet an in vivo model of how flux towards lignin is controlled is lacking. To address this deficiency, we formulated and parameterized a kinetic model based on data from feeding Arabidopsis thaliana basal lignifying stems with ring labeled [13C6]-Phe. Several candidate models were compared by an information theoretic approach to select the one that best matched the experimental observations. Here we present a dynamic model of phenylpropanoid metabolism across several subcellular compartments that describes the allocation of carbon towards lignin biosynthesis in wild-type Arabidopsis stems. Flux control coefficients for the enzymes in the pathway starting from arogenate dehydratase through 4-coumarate: CoA ligase were calculated and show that the plastidial cationic amino-acid transporter has the highest impact on flux.

Ionic-liquid-mediated pretreatment and enzymatic saccharification of Prosopis sp. biomass in a consolidated bioprocess for potential bioethanol fuel production

The efficacy of ionic liquid (IL)-based pretreatment of lignocellulosic biomass (LB) can be enhanced by simultaneous application of surfactants/salts/deep eutectic solvent (DES) systems which may realize more effectual biorefining of LB to biofuels or other commodities. However, due to inhibitory nature of IL, IL-stable saccharification enzymes (cellulase/xylanase) are desired for enzymatic hydrolysis of IL-pretreated biomass. Bacillus spp. are considered as the super microbial factories for production of commercially important robust enzymes. The current study presents the enhanced production (1.438-fold) of an IL-stable cellulase from a newly isolated IL-tolerant Bacillus amyloliquefaciens SV29 by statistical optimization using agroindustrial residues as carbon (groundnut shell) and nitrogen source (mustard cake). The process variables such as groundnut shell and mustard cake, incubation time, and inoculum size were optimized. The enzyme preparation (cellulase/xylanase) was evaluated for its saccharification potential of Prosopis sp. (twigs/pods) biomass that was pretreated either with IL (1-ethyl-3-methylimidazolium methanesulfonate, EMIMS) standalone or IL along with surfactants/salts/DES systems in a consolidated bioprocess (CBP), i.e., one pot consolidated bioprocess, due to several technoeconomic advantages of the latter. No reported studies are available on bioconversion of Prosopis sp. biomass using IL or CBP. Sugar yield was enhanced when IL was used along with either DES choline chloride glycerol (54.4%) or with FeSO4 (51%). Thus, the pretreatment efficacy of EMIMS is substantially enhanced when used in combination with choline chloride glycerol or FeSO4 for getting increased sugar yield upon enzymatic hydrolysis of Prosopis sp. biomass with IL-stable enzymes.

Mechanical fragmentation of wheat and rice straw at different scales: Energy requirement in relation to microstructure properties and enzymatic hydrolysis

Mechanical fragmentation is an important pretreatment step in lignocellulosic biorefinery. In this study, we explored the energy requirement (ER) for mechanical fragmentation of wheat and rice straw at different scales in relation to modifications of microstructure properties and enzymatic hydrolysis. The ER showed a reciprocal relationship with mean particle size (MPZ), but a negative linear relationship with cellulose crystallinity (CrI). An exponential relationship was observed between the ER with a specific surface area (SSA) and the oxygen-to-carbon surface ratio (O/C). The results showed that modification of the cellulose crystallinity required the most energy consumption, whereas reduction of particle size consumed the lowest energy. The order of importance of modifications of different microstructure parameters on the ER was: CrI > O/C > pore volume (PV) > SSA > MPZ. Sugar yield showed a clear, positive linear relationship with ER, indicating that grinding patterns with a high ER could significantly enhance the enzymatic hydrolysis yield owing to the plant cell wall deconstruction. The energy efficiency declined with an increasing ER because of the markedly lower increase in sugar yield compared with the corresponding increase in ER.

Review on Bamboo Utilization as Biocomposites, Pulp and Bioenergy

One of potential non wood bioresources utilized in industrial application is bamboos. Bamboos are include in graminae family which have high biomass productivity, easy and rapid production, wide avability and high holocellulose content. Indonesia has a huge potential of bamboos, more than 162 bamboo species are found however only some of them are planted that have a high economic value. Bamboos have some advantages such as can be harvested at 3 years, straight culm, high strength, easy to be processed, and relatively cheap. Research Center for Biomaterials has developed utilization of bamboo culm for ply bamboo product as alternative of plywood since 1995, using gombong bamboo, tali bamboo, sembilang bamboo, andong bamboo with PF resin as adhesive. Other biocomposite products from bamboos include particle board, cement board and polymer-bamboo fiber composites. In term of processing technique and final product quality, bamboo composites from ply bamboo are the most prospectable material to be utilized in industrial application. Yellow bamboo and betung bamboo have also been developed as pulp and paper. Biopulping using soda and kraft pulping after biological pretreatment using white rot fungi to remove lignin was used as pulping method in this conversion. Biokraft pulping with Trametes versicolor for 45 days with inoculum loading of 10% resulted better pulp quality compared to the other fungi. Betung bamboo had good morphological characteristics and chemical component content to be converted into bioenergy such as bioethanol. Several pretreatment methods have been developed in order to result high sugar yield. Microwave assisted acid hydrolysis was preferedin producing higher yield from the pretreated bamboo compared to enzymatic hydrolysis. By using this method, the bamboo pretreated by biological-microwave pretreatment results higher improvement to increase sugar yield.

Closing the Yield Gap of Sugar Beet in the Netherlands-A Joint Effort.

The reform of the European Union's sugar regime caused potential decreasing beet prices. Therefore, the Speeding Up Sugar Yield (SUSY) project was initiated. At the start, a 3 × 15 target was formulated: in 2015 the national average sugar yield in the Netherlands equals 15 t/ha (60% of the sugar beet potential) and the total variable costs 15 euro/t sugar beet, aspiring a saving on total variable costs and a strong increase in sugar yield. Based on their average sugar yield in 2000-2004, 26 pairs of “type top” (high yielding) and “type average” (average yielding) growers were selected from all sugar beet growing regions in the Netherlands. On the fields of those farmers, all measures of sugar beet cultivation were investigated, including cost calculation and recording phytopathological, agronomical and soil characteristics in 2006 and 2007. Although there was no significant difference in total variable costs, the “type top” growers yielded significantly 20% more sugar in each year compared to the “type average” growers. Therefore, the most profitable strategy for the growers is maximizing sugar yield and optimizing costs. The difference in sugar yield between growers could be explained by pests and diseases (50%), weed control (30%), soil structure (25%) and sowing date (14%), all interacting with each other. The SUSY-project revealed the effect of the grower's management on sugar yield. As a follow up for the SUSY-project, a growers' guide “Suikerbietsignalen” was published, Best Practice study groups of growers were formed and trainings and workshops were given and field days organized. Further, the benchmarking and feedback on the crop management recordings and the extension on variety choice, sowing performance, foliar fungi control and harvest losses were intensified. On the research part, a resistance breaking strain of the Beet Necrotic Yellow Vein Virus (BNYVV) and a new foliar fungus, Stemphylium beticola, were identified and options for control were tested, and implemented in growers practices. The joint efforts of sugar industry, sugar beet research and growers resulted in a raise in sugar yield from 10.6 t/ha in 2002-2006 to 13.8 t/ha in 2012-2016.

The productivity of biological forms of sugar beet as affected by growing season length

Purpose. To find out productivity of biological forms of sugar beet as affected by the length of growing season.Methods. Field, visual, weight measuring, mathematical and statistical.Results. The plant density before harvesting of both biological forms of sugar beet (thousand per hectare) was almost the same: in diploid forms it varied from 105.9 to 106.9 and in triploid ones from 105.6 to 107.0, with LSD05 biological form of 0.56. Increase in the duration of growing season provided a significant increase in root yield. The highest root yield of both biological forms was obtained at the duration of the vegetation of 201 days, that is, at the latest harvesting date (November 10); root yield in diploid and triploid biological forms was 59.2 and 59.9 t/ha, respectively, which was by 6.3 and 6.8 t/ha higher than for the duration of the growing season of 161 days, at early root harvesting (September 30). Increase in the yield of domestic hybrids during October was more intense than that of foreign hybrids. Sugar content in the roots of diploid forms at the duration of vegetation of 161 days (harvesting on September 30) amounted to 15.1%, while at the duration of vegetation of 191 days (harvesting on October 30) it was 15.3 % and for the duration of vegetation of 201 days (harvesting on November 10) 15.6% in triploid forms 14.9%, 15.2% and 15.5%, respectively (LSD05 harvesting time = 0.15%). Sugar yield was affected not only by the biological forms of sugar beet, but also by the soil and climatic conditions. A similar tendency was observed as affected by a hybrid genotype.Conclusions. It was established that the increase in the duration of sugar beet vegetation provided significant increase in root yield and sugar yield in all the biologic forms. 191 days vegetation (30 days increase) and the second harvesting date provided an increase in root yield of diploid and tripod hybrids by 5.0 t/ha, comparing with the 161 days vegetation period. Increase in root and sugar content of both biological forms ensured an increase in sugar yield of 0.9 and 1.0 t/ha, respectively. The maintenance of the vegetation till November 10 (201 days) also had a significant effect on the yield of both diploid and triploid sugar beet forms, as compared to the second one. The increase in the yield of diploid forms was 1.3 t/ha and triploid 1.7 t/ha. However, postponing harvesting for such later period under the conditions of low moisture in the Right-Bank Forest-Steppe of Ukraine is risky. Therefore, 30–40 days prolongation of sugar beet vegetation is one of the main reserves for increasing rood yield, sugar content and yield.

Increased sugar yield from pre-milled Douglas-fir forest residuals with lower energy consumption by using planetary ball milling

Impact of planetary ball milling on pre-milled wood fiber was studied to improve efficiency of energy consumption for bioconversion using post-harvest forest residuals. Crystalline cellulose decreased from 40.73% to 11.70% by ball milling. Crystallinity index of ball milled wood samples had a negative correlation with glucose yield (r = −0.97, p < .01), xylose/mannose (r = −0.96, p < .01), and a positive correlation with median particle size (r = 0.77, p < .01). Range of glucose yield and xylose/mannose yield for ball milled samples was found to be 24.45–59.67% and from 11.92% to 23.82%, respectively. Morphological changes of the lignocellulosic biomass were observed; the compact fiber bundles of the forest residuals were cleaved to smaller particles with lower aspect ratio with increasing intensity of ball milling. The required energy ranged from 0.50 to 2.15 kWh/kg for 7–30 min of milling respectively.

Microwave-assisted inorganic salt pretreatment of sugarcane leaf waste: Effect on physiochemical structure and enzymatic saccharification

This paper presents a method to pretreat sugarcane leaf waste using microwave-assisted (MA) inorganic salt to enhance enzymatic saccharification. The effects of process parameters of salt concentration, microwave power intensity and pretreatment time on reducing sugar yield from sugarcane leaf waste were investigated. Pretreatment models based on MA-NaCl, MA-ZnCl2 and MA-FeCl3 were developed with high coefficients of determination (R2 >0.8) and optimized. Maximum reducing sugar yield of 0.406g/g was obtained with 2M FeCl3 at 700W for 3.5min. Scanning electron microscopy (SEM), Fourier Transform Infrared analysis (FTIR) and X-ray diffraction (XRD) showed major changes in lignocellulosic structure after MA-FeCl3 pretreatment with 71.5% hemicellulose solubilization. This regime was further assessed on sorghum leaves and Napier grass under optimal MA-FeCl3 conditions. A 2-fold and 3.1-fold increase in sugar yield respectively were observed compared to previous reports. This pretreatment was highly effective for enhancing enzymatic saccharification of lignocellulosic biomass.

Interaction Effects of 6-Benzylaminopurine, Indole-3-Butyricacid and Urea Fertilizer to Enhance Tillering Potential of Sugarcane (Sacharum officinarum L) Plants

Even though tillering is a key yield attribute in sugarcane and determined by the genetic base of the genotype, it can also be affected by applications of plant growth regulators, phenolic compounds, nitrogen fertilizers and other agronomic management practices. With this view, the effects of BAP, IBA and Urea fertilizer on two sugarcane genotypes with early maturing and high sugar content but shy in tillering followed by few millable stalk populations and hence low in cane and sugar yield was investigated. Accordingly, three levels of BAP (0, 0.03 & 0.06 mg/l), three levels of IBA (0, 0.02 and 0.03 mg/l) and four levels of Urea (0, 300, 450 and 700 kg/ha) with two sugarcane genotypes in a completely randomized block design with 3*3*4*2 factorial treatment combination arrangements was tested. Data on the number of tillers per shoot, average shoot length (cm) and number of active leaves per shoot were collected after 60 days of planting on Luvisol of Metahara Sugar Estate. Analysis of variance proved that the interaction effects of BAP* IBA*Urea*Sugarcane genotypes was highly significant (P<0.001) on the response variables tested. In sugarcane genotype C132-81, the optimum number of tillers per shoot (11.43) was obtained at 0.03 mg/l IBA, 0.06 mg/l BAP and 300 kg/l Urea fertilizer with 30.47 cm average shoot length and 8.27 active leaves per shoot while C86-56 produced 10.97 tillers per shoot with 33 cm average shoot length and 6.57 active leaves per shoot on the same treatment combination. From this result, it can be deduced that, it is possible to double the key yield attribute; number of tillers per shoot in shy tillering sugarcane genotypes that can in turn increase cane and sugar yield.

Impact of Harvest Time and Switchgrass Cultivar on Sugar Release Through Enzymatic Hydrolysis

Switchgrass (Panicum virgatum L.) is a native North American prairie grass being developed for bioenergy production in the central and eastern USA. The objective of this study was to identify the impacts of harvest time and switchgrass cultivar had on sugar release variables determined through enzymatic hydrolysis. Previously, we reported that delaying harvest of switchgrass until after frost and until after winter resulted in decreased yields of switchgrass but it reduced the amount of ash and nutrients in the biomass. The current study used near-infrared reflectance spectroscopy (NIRS) to broaden an existing set of calibration equations designed to predict composition and sugar release variables of switchgrass. These updated calibrations were then applied to the full set of samples from a multi-year and multi-location switchgrass harvest-management study. Composition and processor sugar yields were significantly affected by location, year, cultivar, and harvest time, of which the time of harvest was the most important. Delaying the time of harvest until after frost or post-winter increased the concentration of structural carbohydrates from 500 to over 570 g kg−1 in the biomass and lignin content from 160 to over 200 g kg−1. Conversely, delaying harvest time lowered the amounts of ash and soluble sugars. The later harvest times also yielded more sugars following processing with yields increasing over 20% from the first harvest. Increased sugar yields are attributable to both increased concentration of sugars in the biomass upon harvest and reduced biomass recalcitrance. Based upon processed sugar yields, it is estimated that a biorefinery producing 76 million liters of ethanol per year would require 229–373 km2 of land cultivated with switchgrass.

A Comparison of Various Technological Options for Improving Energy and Water Use Efficiency in a Traditional Sugar Mill

This study is a comparison of four technological improvements proposed in previous works for the Cuban sugar mill Carlos Baliño. These technological options are: (1) utilization of excess wastewater for enhanced imbibition; (2) utilization of waste heat for thermally driven cooling; (3) utilization of excess bagasse for pellets; and (4) modification of the cogeneration unit for maximum electric power generation. The method used for the evaluation of the technological options involves using criteria such as energy saving, financial gains, and CO2 emission saving potential. The results of the analysis show that the first three technological improvement options are attractive only during the crushing season. On the other hand, the last technological improvement option can be attractive if a year round generation of surplus power is sought. The first technological improvement option leads to only minor changes in energy utilization, but the increase in sugar yield of 8.7% leads to attractive profitability with an extremely low payback period. The CO2 emissions saved due to the fourth technological improvement option are the highest (22,000 tonnes/year) and the cost of CO2 emissions saved for the third technological improvement option (lowest) amount to 41 USD/tonne of CO2 emissions saved. The cycle efficiencies of the third and fourth technological improvement options are 37.9% and 36.8%, respectively, with payback periods of 2.3 and 1.6 years. The second technological improvement option is the least attractive alternative of the group.

Cultivar genetic gains from 50 years of irrigated sugarcane breeding in South Africa

Cultivar genetic gains provide a measure of benefits to growers from sugarcane breeding programmes and determine the effectiveness of cultivar development. The objective of this study was to determine the genetic gains for cane yield, percent estimated recoverable crystal (ERC%) cane and sugar yield of cultivars developed for the irrigated regions of South Africa after 50 years of sugarcane breeding. Data were derived from advanced cultivar trials planted in the early and mid-season in the Pongola and Mpumalanga regions. Significant (p < 0.01) cultivar differences were observed for cane and sugar yield and ERC% cane. There were significant (p < 0.05) season effects on ERC% cane and significant (p < 0.01) season by cultivar effects on ERC% cane and sugar yield, suggesting seasonal adaptation of cultivars. Cultivar genetic gains of 0.26 Mg ha−1 y−1 for cane yield, 0.03 Mg ha−1 y−1 for sugar yield and 0.06% y−1 for ERC% cane were observed. Genetic gains by sequence of release were 0.31 Mg ha−1 cultivar−1 for cane yield, 0.09 Mg ha−1 cultivar−1 for sugar yield and 0.06% cultivar−1 for ERC% cane. Cultivars released after 2000 produced genetic gains equivalent to 6% increase in sugar yield and 9% increase in ERC% cane compared with those released before 1990.

Investigation on characteristics of corn stover and sorghum stalk processed by ultrasonic vibration-assisted pelleting

Cellulosic ethanol produced from cellulosic biomass is an alternative to petroleum-based liquid transportation fuels. The cost-effectiveness of cellulosic ethanol manufacturing has been hindered by several technical barriers. One such barrier is that low density of biomass causes high costs of biomass transportation, handling, and storage. Another barrier is low sugar yield in enzymatic hydrolysis, making enzymatic hydrolysis an expensive and slow step. Ultrasonic vibration-assisted (UV-A) pelleting of cellulosic biomass can increase its density and reduce the costs of biomass transportation and handling. In addition, sugar yield of biomass pellets processed by UV-A pelleting was higher than that of particles (unpelleted biomass) with diluted acid pretreatment. The reason that UV-A pelleting could increase sugar yield of biomass is still unclear. The objective of this study was to investigate reasons that UV-A pelleting combined with diluted acid pretreatment could increase sugar yield of biomass. High sugar yield is preferred to achieve high ethanol yield. Effects of UV-A pelleting on biomass characteristics (such as chemical composition, crystallinity index, thermal properties, and morphological structure) were investigated. The results showed there was no significant difference in chemical composition between pellets and particles. However, crystallinity of biomass increased after UV-A pelleting. In addition, pellets had higher decomposition temperature than particles, indicating that pellets were more thermally stable than particles. Examinations on morphological structure of biomass showed that softened surface regions of biomass were removed and cellulose microfibrils were revealed after UV-A pelleting.

Microwaves as a pretreatment for enhancing enzymatic hydrolysis of pineapple industrial waste for bioethanol production

The pineapple industry generates significant amounts of residues which are classified as lignocellulosic residual biomass. In the present paper, microwaves are studied as a pretreatment to improve pineapple waste saccharification. Different microwave (MW) powers (10.625, 8.5, 6.375, 4.25 and 2.125W/g) and exposure times (1–20min) were applied to the solid part of the waste before enzymatic hydrolysis. Infrared thermography was used to assess temperature evolution and structural modifications were evaluated by Cryo-SEM. Sugar content and fermentation inhibitors (phenols, furfural and hydroxymethylfurfural) were also determined. MW increased sugar yield as long as intermediate powers were used (up to 6.375W/g). However, high powers and longer treatments resulted in sugar degradation and/or a decrease in the efficiency of the enzymatic hydrolysis process. Temperature records indicated that thermal sugar degradation may occur in those cases. The presence of fermentation inhibitors have been confirmed and related to prolonged MW treatments. Microscopic observations suggested that mild microwave pretreatments may promote microstructural changes that enhance enzyme performance, whereas harsher treatments could increase tissue compactness and reduce the effectiveness of the enzymatic treatment. It is concluded that microwave pretreatments using the appropriate energy supply and exposure time enhances saccharification efficiency, potentially improving further bioethanol yield.

Effect of solids loading and solvent type on the enzymatic hydrolysis of cellulose

AbstractBACKGROUNDSolvent based pretreatment of biomass followed by enzymatic hydrolysis (in the presence of the solvent – ‘in situ hydrolysis’) is an attractive route to develop a biorefinery concept since it reduces a number of washing steps to remove the solvent and saves energy. This work explores the ability of the commercial ‘lyocell’ solvent ‐ N‐methyl Morpholine N‐Oxide (NMMO) for ‘in situ’ hydrolysis at high cellulose loadings and compares its hydrolysis performance with commercially available ionic liquids (ILs).RESULTSNMMO is able to dissolve high loadings of cellulose which on subsequent in situ enzymatic hydrolysis results in not only an increased sugar yield (∼30 mg mL−1) but also an enhanced rate of hydrolysis (12.24 mg mL−1 h−1). In addition, a comparative study of hydrolysis in the presence of NMMO and ILs reveals the fact that hydrolysis in NMMO produces the highest sugar yields when compared with ILs.CONCLUSIONThis study thus establishes the effectiveness of NMMO as a pretreatment solvent – it is an excellent solvent for disrupting the microstructure and dissolving high loadings of cellulose, and hydrolysis reactions can be carried out in the presence of NMMO since enzymes are active in its presence. © 2016 Society of Chemical Industry

Effect of zinc band application on sugar beet yield, quality and nutrient uptake

The yield-forming effect of sugar beet fertilization with nitrogen (N) depends on many factors, including the components controlling N metabolism such as zinc (Zn). Two field experiments on soil with an average content of available Zn were conducted to verify the hypothesis. The component was deep band-applied in the form of ZnO suspension together with urea ammonium nitrate, UAN (72 kg/ha). The rates of Zn were as follows: 0; 0.5; 1.0; 1.5 and 2.0 kg/ha. The beet yield (BY) increased in accordance with the Zn rate. The significant BY increase compared to the control was recorded at a level of 1.5 and 2.0 Zn kg/ha, amounting to 14.5% and 21.8%, respectively. The best quality of taproots reflected in biological sugar content was observed at a level of 0.5 kg/ha. In the result, already the rate of 0.5 kg/ha significantly increased sugar yield compared to the control. The effect of Zn application on the nutrient content and uptake depended on the vegetation season, investigated part of the plant and the element. The examined factor significantly affected Zn content in leaves and N in the taproots. Only a total Zn uptake, independently of the seasonal factor, considerably depended on the fertilization applied.

Evaluating the Effects of Chemical Ripening with Fluazifop-p-butyl on Sugarcane (Saccharum officinarum) Yield and Sugar Content

Ripening in sugarcane refers to an increase in sugar content on a fresh weight basis prior to commercial harvesting. Ripening is often prompted by use of chemicals and environmental cues such as moisture stress. The aim of this research was to determine the effects of Fluazifop- pbutyl, a chemical ripener on sugarcane yield and sugar content. The experiment was laid out as a Random Complete Block Design (RCBD) with five replications. Treatments were: Fluazifop- p- butyl (0.45 lha-1), drying off, Fluazifop- p- butyl (0.45 lha-1) + drying off and the control (no Dry off, no Fluazifop- p- butyl). The experiment was carried out at Triangle Estate which is located in the South East Lowveld of Zimbabwe from March 2012 to May 2012. Data on sugarcane yield, sugar quality (Pol % and ERC %) and sugar yield was collected 56 days after establishment of the experiment. Analysis of variance was done on yield and quality data using Genstat 14th edition. Results showed that there were significant differences (P = 0.05) among treatments on sugarcane yield, sugar yield, Pol% and ERC%. The sugarcane yield was highest for the control where no ripener was used. Fluazifop- p- butyl treatment attained 13.9% lower sugarcane yield relative to the control. Application of Fluazifop- p- butyl resulted in the highest sugar yield which was 35.6% higher than that of the control where no ripener was used. A combination of Fluazifop- p- butyl and Dry of resulted in the highest Pol % and highest ERC %. It can be concluded that Fluazifop- p- butyl is effective in increasing sugar yield although it results in a reduction in sugarcane yield. Combining Fluazifop- p- butyl with Dry off results in increased Pol% and ERC%. There is need for further studies to determine the optimum period from spraying Fluazifop- p-butyl to harvesting of sugarcane as this was only done at the end of the drying-off period.