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Highlights • N rate exhibited non-significant effects on biofuel feedstock quality indices but significantly improved TEY. • CP content and protein yield as forage quality increased with application of 60 kg N ha−1. • Late summer harvest provides best quality forage while early fall harvest supplied more TEY. • Soil NO 3 − content at early fall harvest increased with increasing N rate. • A lower N rate was suitable to produce quality forage or feedstock and to avoid NO 3 − leaching on sandy soil. Abstract Switchgrass (Panicum virgatum L.) is a perennial warm-season grass which has great potential as a forage or bioenergy crop in marginal land. This study was conducted to determine whether nitrogen (N) fertilization could affect biomass quality of switchgrass harvested in late summer and early fall. The effects of four N fertilizer application rates (0, 60, 120, and 240 kg N ha−1) and two harvest times (late summer and early fall) on the quality components of forage and biofuel feedstock and theoretical ethanol yield (TEY) were investigated on a sandy wasteland (Aridisol) in Inner Mongolia, China during the growing seasons of 2015 and 2016. Soil NO 3 − content was also examined in response to N application rates. Application of 60 kg N ha−1 significantly increased switchgrass crude protein (CP) content, protein yield, and TEY (p < 0.05), but did not affect other quality parameters of forage and biofuel feedstock. Compared with the late summer harvest, CP content and protein yield were significantly lower, while TEY was significantly higher in the early fall harvest (p < 0.05); however, cellulose, hemicellulose, and ash contents showed no significant differences between the two harvest times. Acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents were significantly lower for harvest in early fall than in late summer (p < 0.05). Soil NO 3 − content in early fall harvest increased significantly with increasing N application rate (p < 0.05), and was lower than that in the switchgrass green-up stage. These findings together with our results on biomass yield and apparent soil N balance suggest that a lower rate of N application appears sufficient to produce good quality forage as well as biomass without negatively affecting feedstock quality, while avoiding the risk of NO 3 − loss via leaching on a sandy soil. Switchgrass forage quality would be high during summer in terms of CP content, although delaying harvest until fall or even after a killing frost could provide better quality feedstock for bioenergy production. [ABSTRACT FROM AUTHOR]

Improper management of cattle manure and poultry litter from confined animal farming are usually source of water pollution. However, appropriate application of these products on switchgrass ( Panicum virgatum L.) field can enhance biomass yield and promote nutrient recycling. We evaluated the effects of harvest frequency and nutrient sources on yield and quality of switchgrass for biofuel feedstock. The experiment was carried out at Perkins and Lake Carl Blackwell, Oklahoma, from 2009 to 2011 using split plot design with four replications. The main plot treatments were two harvest frequencies single (June), and twice (June and November). The subplot treatments were nutrient sources: 1) cattle manure (CM), 2) poultry litter (PL), 3) urea (nitrogen at 150 kg ha −1 ), 4) combined chemical fertilizer (nitrogen-P 2 O 5 –K 2 O) with nitrogen at 150 kg ha −1 , P 2 O 5 at 40 kg ha −1 , and K 2 O at 20 kg ha −1 , 5) inter-seeded Crimson clover ( Trifolium incarnatum L.), and 6) control. Mean biomass yield was higher (12.4 Mg ha −1 ) in 2010 than other years possibly due to optimum moisture and temperature in 2010. At Perkins in 2010, application of CM and PL increased biomass yield significantly by 30 and 23% compared with combined chemical fertilizer (12.9 Mg ha −1 ). The effect of nutrient sources on cellulose, hemicellulose and lignin content was not significant at both locations. Cumulative biomass from twice harvest was similar to single harvest except in 2011 due to dry weather after the first cut. The cellulose and lignin content were significantly higher for single harvest compared with twice harvest at both locations. [ABSTRACT FROM AUTHOR]

Marginal and degraded lands are expected to be important resources in the production of biofuel feedstocks in order to avoid real or perceived competition with food, feed and fiber production. Globally, there are millions of hectares of salt-affected land available for lignocellulosic feedstock production. Greenhouse experiments determined the effects of irrigating with water having different levels of salinity and sodicity on seedling emergence, plant growth, and cation balance in plant tissues in several populations of switchgrass ( Panicum virgatum L.) and prairie cordgrass ( Spartina pectinata Link). The effect of salt stress on seedling emergence was more pronounced in switchgrass than prairie cordgrass with 31 and 15% reduction, respectively, compared with pure water. In a two-season greenhouse pot experiment, aboveground dry biomass production in control treatments was 8 and 21% higher in prairie cordgrass pc17-102 and pc17-109, respectively, than in EG 1102 switchgrass. Switchgrass EG 1102 produced greater biomass than prairie cordgrass populations when irrigated with moderately saline (5 dS m −1 ) water, although differences were not detected with highly saline water (10 dS m −1 ). Switchgrass EG 2101 emergence, plant growth and cation balance were severely affected by increasing levels of salinity. Overall, several prairie cordgrass populations and lowland switchgrass cultivars were found to have good emergence and high biomass production under moderate to high salt stress and may be good candidates for lignocellulosic feedstocks on salt-affected land. [ABSTRACT FROM AUTHOR]

The potential use of lignocellulosic biomass as the feedstock for fumaric acid production and to select the specific Rhizopus oryzae strain for bioproduction was investigated in the current work. For this purpose, alkaline pretreatment of the biomass from perennial grasses, silver grass (Miscanthus sp.) and switchgrass (Panicum virgatum), and hemp (Cannabis sativa) was performed followed by enzymatic saccharification. The hydrolysate so obtained, was used as the feedstock for fumaric acid production. Silver grass was identified as the ideal perennial lignocellulosic biomass due to its higher reducing sugar concentration of 39.55 g/L as well as a yield of 0.79 g/g of pretreated biomass. The use of the hydrolysate for fumaric acid production, by three R. oryzae strains namely NRRL 1526, NRRL 6400 and NRRL 2582, yielded acid concentrations of 8 – 9 g/L. The strain NRRL 1526 was identified as the promising strain for fumaric acid bioproduction, as it provided the highest fumaric acid productivity of 0.19 gL−1h−1. [Display omitted] • High biomass yielding grasses and hemp used as feedstock • Miscanthus sp. (silvergrass) identified as the promising feedstock • Silvergrass yielded 0.38 g/g of sugar to achieve concentration of 39 g/L • 8–9 g/L fumaric acid obtained with yields of 0.3–0.5 g/g • Three Rhizopus oryzae strains investigated for fumaric productivity [ABSTRACT FROM AUTHOR]

Abstract: To improve the cost-effectiveness of biomass-to-sugar conversion, sodium hydroxide (NaOH) pretreatment of switchgrass was carried out at 21°C using previously determined optimum conditions (2% NaOH (w/v), 6h), and the spent alkaline liquid (black liquor) was collected and used for pretreatment of corn stover, a feedstock exhibiting a higher susceptibility to NaOH attack, for improved enzymatic hydrolysis at a reduced cost. The results showed that, because of the high pH and the appreciable amount of carbohydrates in the black liquor, sugar production during enzymatic hydrolysis of corn stover pretreated with black liquor was comparable to that of biomass pretreated with 1% NaOH. After black liquor pretreatment at the best residence time (24h), the total reducing sugar, glucose, and xylose yields of corn stover reached 478.5, 287.7, and 145.3mg/g raw biomass, respectively, indicating the viability of this novel pretreatment technology. [Copyright &y& Elsevier]

Abstract: Different types of feedstocks, including corn stover, wheat straw, soybean straw, switchgrass, and hardwood, were tested to evaluate the effectiveness of fungal pretreatment by Ceriporiopsis subvermispora. After 18-d pretreatment, corn stover, switchgrass, and hardwood were effectively delignified by the fungus through manganese peroxidase and laccase. Correspondingly, glucose yields during enzymatic hydrolysis reached 56.50%, 37.15%, and 24.21%, respectively, which were a 2 to 3-fold increase over those of the raw materials. A further 10–30% increase in glucose yields was observed when pretreatment time extended to 35d. In contrast, cellulose digestibility of wheat straw and soybean straw was not significantly improved by fungal pretreatment. When external carbon sources and enzyme inducers were added during fungal pretreatment of wheat straw and soybean straw, only glucose and malt extract addition improved cellulose digestibility of wheat straw. The cellulose digestibility of soybean straw was not improved. [Copyright &y& Elsevier]

Abstract: Switchgrass, a perennial warm-season grass and potential energy crop, is usually harvested during the time between full maturity in the fall to the following spring. During this wide harvest window, the changes in fuel properties that could occur are important for making appropriate decisions with respect to the optimum harvest time for maximum fuel quality. A field plot study was carried out to investigate the quantitative fuel properties (proximate, ultimate and mineral analyses) of switchgrass over a harvest period from crop maturity in July through November. Harvest moisture decreased from July to November and moisture was uniformly distributed in the switchgrass plant at all times in the harvest period. There were significant differences in ash, volatiles, fixed carbon and nitrogen among months of harvest. Nitrogen, ash and fixed carbon contents decreased while oxygen and volatiles increased through the harvest period. Also, there were significant differences in oxides of silicon, calcium, potassium, phosphorus and sulfur among harvest times. The concentration of oxides of potassium and sulfur decreased at the end of the harvesting period. Fouling and slagging indices decreased as harvest was delayed but remained low throughout harvest. However, the decreases are small and might not dramatically impact fouling and slagging. Overall, the results appear to favor a later harvest for switchgrass used for direct combustion. This study will benefit feedstock producers as well as biomass feedstock facility operators by providing a better understanding of how the properties of switchgrass vary over a typical harvest period and their potential effect on boiler equipment. [Copyright &y& Elsevier]

Abstract: Switchgrass (Panicum virgatum L.) is a warm season perennial grass with great potential as an energy crop in the USA. It is widely adapted to many regions of the country, produces large amounts of biomass, serves as a useful forage grass, and provides ecosystem services that benefit soil and water quality and wildlife. Biological and thermochemical technologies are being developed to convert herbaceous biomass, including switchgrass, to energy. The objective of this research was to determine the effect of genotype and production environment on the concentration of minerals that affect the suitability of switchgrass for thermochemical conversion and to quantify the amount of potassium (K) and phosphorus (P) removed from the production system by harvest of the aboveground biomass, a measure of the sustainability of the practice. Straw dry biomass contained from 1.3 to 6.4kgMg−1 and from 6.2 to 15.8kgMg−1 of P and K, respectively. Variability in aluminum (Al), calcium (Ca), chloride (Cl), K, P, silicon (Si), and sulfur (S) concentrations across locations was relatively high, ranging from twofold (Al) to eightfold (Cl). Location had a strong impact on mineral concentrations among switchgrass genotypes evaluated in this study. Latitude of origin impacted the Cl and Si concentrations measured in plant tissues, but none of the other minerals analyzed in this study. Upland and lowland cytotypes explained some of the observed differences, but population×location interactions were the primary source of variability in the concentration of these minerals. [Copyright &y& Elsevier]

Abstract: The effects of five different biomass species and their chemical composition on the overall process efficiency and economic performance considering feedstock availability and feedstock costs to manufacture ethanol from lignocellulose were studied. First is a comparison of ethanol production and excess electricity generated between different biomass species. Results show that, at the same feedstock rate of 2000Mgday−1, aspen wood has larger ethanol production than switchgrass, hybrid poplar and corn stover, while the excess electricity generated is as follows in increasing order: aspen