Application of Ionic Liquids in the Utilization of the Agricultural Wastes: Towards the One-Step Pre-Treatment and Cellulose Hydrolysis

The goal of this study is to estimate the county-level environmental performance for continuous corn cultivation of corn grain and corn stover grown under the current tillage practices for various corn-growing locations in the US Corn Belt. The environmental performance of corn grain varies with its farming location because of climate, soil properties, cropping management, etc. Corn stover, all of the above ground parts of the corn plant except the grain, would be used as a feedstock for cellulosic ethanol. Two cropping systems are under investigation: corn produced for grain only without collecting corn stover (referred to as CRN) and corn produced for grain and stover harvest (referred to as CSR). The functional unit in this study is defined as dry biomass, and the reference flow is 1 kg of dry biomass. The system boundary includes processes from cradle to farm gate. The default allocation procedure between corn grain and stover in the CSR system is the system expansion approach. County-level soil organic carbon dynamics, nitrate losses due to leaching, and nitrogen oxide and nitrous oxide emissions are simulated by the DAYCENT model. Life cycle environmental impact categories considered in this study are total fossil energy use, climate change (referred to as greenhouse gas emissions), acidification, and eutrophication. Sensitivities on farming practices and allocation are included. Simulations from the DAYCENT model predict that removing corn stover from soil could decrease nitrogen-related emissions from soil (i.e., N2O, NO x , and NO3 − leaching). DAYCENT also predicts a reduction in the annual accumulation rates of soil organic carbon (SOC) with corn stover removal. Corn stover has a better environmental performance than corn grain according to all life cycle environmental impacts considered. This is due to lower consumption of agrochemicals and fuel used in the field operations and lower nitrogen-related emissions from the soil. The primary source of total fossil energy associated with biomass production is nitrogen fertilizer, accounting for over 30% of the total fossil energy. Nitrogen-related emissions from soil (i.e., N2O, NO x , and NO3 − leaching) are the primary contributors to all other life cycle environmental impacts considered in this study. The environmental performance of corn grain and corn stover varies with the farming location due to crop management, soil properties, and climate conditions. Several general trends were identified from this study. Corn stover has a lower impact than corn grain in terms of total fossil energy, greenhouse gas emissions, acidification, and eutrophication. Harvesting corn stover reduces nitrogen-related emissions from the soil (i.e., N2O, NO x , NO3 −). The accumulation rate of soil organic carbon is reduced when corn stover is removed, and in some cases, the soil organic carbon level decreases. Harvesting only the cob portion of the stover would reduce the negative impact of stover removal on soil organic carbon sequestration rate while still bringing the benefit of lower nitrogen-related emissions from the soil. No-tillage practices offer higher accumulation rates of soil organic carbon, lower fuel consumption, and lower nitrogen emissions from the soil than the current or conventional tillage practices. Planting winter cover crops could be a way to reduce nitrogen losses from soil and to increase soil organic carbon levels. County-level modeling is more accurate in estimating the local environmental burdens associated with biomass production than national- or regional-level modeling. When possible, site-specific experimental information on soil carbon and nitrogen dynamics should be obtained to reflect the system more accurately. The allocation approach between corn grain and stover significantly affects the environmental performance of each. The preferred allocation method is the system expansion approach where incremental fuel usage, additional nutrients in the subsequent growing season, and changes in soil carbon and nitrogen dynamics due to removing corn stover are assigned to only the collected corn stover.

Integrated bioethanol production from mixtures of corn and corn stover

Comparison of forage yield, silage fermentative quality, anthocyanin stability, antioxidant activity, and in vitro rumen fermentation of anthocyanin-rich purple corn (Zea mays L.) stover and sticky corn stover

Addition of additives has been confirmed to increase cellulase performance in the hydrolysis of lignocellulosic materials. In the hydrolysis of xylan-containing lignocellulosic biomass, xylanase can synergistically enhance the performance of cellulase. However, the role of additives in xylan hydrolysis by xylanase is not yet clear. In this work, with the presence of additives (bovine serum albumin, poly(ethylene glycol), and Tween), the hydrolysis of isolated xylan and the xylan in corn stover increased to different extents. Additives increased free xylanase in supernatants in the hydrolysis with xylanase, indicating the reduction of the adsorption of xylanase on corn stover and insoluble xylan. Enhanced hydrolysis of Avicel and corn stover by additives suggested that besides the prevention of unproductive binding of xylanase to lignin by additives, reducing the adsorption of xylanase on substrates was also contributed to enzymatic hydrolysis. The increment of xylanase activity by additives suggests that the additives were activators of xylanase. The results of this work indicate that the supplementation of additives could improve xylanase performance, synergistically enhanced the cellulose hydrolysis, and beneficial for the recycling of xylanase.

As a type of agricultural waste, there is a large amount of lignocellulose in corn (Zea mays) straw, but it is difficult to utilize efficiently owing to its recalcitrance to enzymatic degradation. Three strains of actinomycetes that degrade cellulose were constructed as complex flora, and the conditions of cellulose degradation conditions and their degradative activity were optimized and evaluated. When the complex flora were inoculated into the fermentation medium at pH 7 and 3% (v/v), the rate of degradation of corn straw reached 38.24% after 5 d of fermentation at 28ºC and 180rpm. Cellulose, hemicellulose, and lignin in the corn straw were degraded by 33.97%, 34.08%, and 21.52%, respectively. The results from scanning electron microscopy showed that the waxy layer on the surface of corn straw became thin and gradually disappeared following fermentation by the complex flora. Fourier-transform infrared spectroscopy showed that the complex flora could change the internal functional groups of corn straw at different fermentation periods. The compounds detected in the fermentation system indicated that the corn straw was efficiently degraded. These results indicated that the constructed complex flora was more effective at degrading corn straw than the individual strains and provides research concepts for the development and utilization of biomass resources.

Nutritive value of fresh or fermented total mixed ration (TMR) containing Chinese wildrye (Leymus chinensis (Trin.) Tzval.) or dry corn (Zea mays L.) stover was determined. The experimental treatments included fermentation and dietary roughage. The fermentation treatments included fresh and fermented TMR, while the dietary roughage treatments included Chinese wildrye and corn stover. Compared to the fresh TMR, the fermented TMR had higher (P < 0.05) contents of ether extract, lactic acid, acetic acid and ammonia‐nitrogen (N) but lower (P < 0.05) organic matter, non fibrous carbohydrate and neutral detergent fiber, and inhibited growth of molds in silages; moreover, the fermented TMR increased (P < 0.05) the digestibility of ether extract and neutral detergent fiber, and tended to increase (P < 0.05) the digestibility of acid detergent fiber, but also increased the concentration of ruminal total volatile fatty acid and valeric acid at 2 h of feeding, and ammonia‐N at 2 or 4 h of feeding. The silage with 10 mm corn stover had a higher (P < 0.05) lactic acid content, and reduced (P < 0.05) losses of non fibrous carbohydrate during fermentation compared with 50 mm treatment. Almost all chopped‐corn stover TMR had similar nutrient digestibility to Chinese wildrye. Among the eight TMRs, the fermented TMR with 10 mm corn stover had the highest intake ration of dry matter, while the fermented TMR with Chinese wildrye was the lowest. These results suggest that fermentation inhibit growth of molds in silage, decrease neutral detergent fiber, and then improve the nutrient digestibility. Chopped corn stover TMR had similar nutrient digestibility to Chinese wildrye TMR, and could replace Chinese wildrye in TMRs for ruminants.

A mechano-biocatalytic one-pot approach to release sugars from lignocellulosic materials

Anaerobically digested sewage sludge resulting from treatment of sewage with Ca(OH)2, Al2(SO4)3, or FeCl, for phosphorus precipitation were applied at rates supplying up to 1,600 kg N/ha each year to corn (Zea mays L.) and bromegrass (Bromus inermis Leyess). Treatments with NH4NO3 supplying up to 400 kg N/ha were included.Soil PH was increased by Ca‐sludge and reduced slightly by Fe‐sludge application. Phosphorus and magnesium concentrations in corn grain and stover were unaffected by treatment. Phosphorus concentration in bromegrass, and NaHCO3‐soluble soil P, were increased by Ca‐sludge and, to a lesser extent, by Fe‐sludge additions. The Ca‐sludge treatments resulted in a lower K concentration in corn stover and seedlings than either Al‐ or Fe‐sludge treatments. Increasing sludge or NH4NO3 application reduced K concentration in bromegrass. Both sludge and NH4NO3 applications decreased ammonium acetate‐extractable soil K in the bromegrass experiment. Sludge application had no effect on Ca concentration in corn grain or stover from Conestoga loam and Caledon loamy sand, but increased it in corn seedlings and stover from Oneida clay loam. Calcium in bromegrass was increased by sludge treatment with the Ca‐sludge having the greatest effect. Magnesium in bromegrass was increased by sludge and by NH4NO3 applications. The Ca‐sludge decreased Mg extracted by ammonium acetate from the loam and clay loam soils but not from the loamy sand.

Biochars are used for soil fertility improvement because they may contain certain elements that plants use as nutrients. However, few studies have demonstrated enhanced crop nutrient uptake. Our study examined nutrient uptake responses of corn (Zea Mays L.) grain and stover over 4 years (Y) after a Goldsboro sandy loam (fine-loamy, siliceous, sub-active, thermic Aquic Paleudults) received different designer biochars and a compost. The designer biochars were produced from lodgepole pine (Pinus contorta) chip (PC), poultry litter (PL), blends with switchgrass (SG; Panicum virgatum), and a SG compost alone. Topsoil treated with 100% PL biochar and blended PC:PL biochar had significantly greater Mehlich 1 (M1) extractable P, K and Na contents compared to the control or other treatments. No significant differences were detected in annual grain nutrient concentrations. In the first corn stover harvest (Y1), significantly greater concentrations of P and K were taken up after treatment with 100% PL biochar, with PC:PL blend and with SG when compared to control. By the fourth corn stover harvest (Y4), nutrient uptake between treatments was not significantly different. Biochar impact on corn stover P, K and Na concentrations was time dependent, suggesting that repeated biochar applications may be needed.

Abstract. This study aims to determine the calcium (Ca) and phosphorus (P) content of complete feed silage made from corn straw (Zea mays) with the addition of Azolla (Azolla pinnata) as ruminant animal feed. complete feed silage research used a completely randomized design (crd) with 4 treatments and 3 replications. The complete feed treatments applied in this study were: S1= 50% corn straw+30% azolla+19% rice bran+1% mineral mix, s2=50% corn straw+25% azolla+24% rice bran+1 % mineral mix, s3= 50% corn straw+20% azolla+29% rice bran+1% mineral mix, s4=50% corn straw+15% azolla+34% rice bran+1% mineral mix. The results of the analysis of variance showed that the calcium content of complete feed silage made from corn straw (Zea mays) with the addition of azolla at S1, S2, S3, S4 had no significant effect (P> 0.05), the average calcium (Ca) content of the feed was S1 (1.033%), S2 (1.036%), S3 (1.17%) and S4 (0.92%). Treatment S1 was not significantly different from the treatment S2, S3 and S4, S2 was not significantly different from S1, S3, and S4, S3 was not significantly different from S1, S2, and S4 and S4 was not significantly different from S1, S2, and S3. While the calcium content of complete feed silage made from corn straw (Zea mays) with the addition of azolla at S1, S2 and S3 had a significant effect (P<0.05). The average phosphorus content of feed is S1(1, %), S2(1.1%), S3(1.17%) and S4(1.03%). S1 treatment was not significantly different from S4 treatment and significantly different from S2 and S3, S2 was not significantly different from S3 and S4 and significantly different from S1, S3 was significantly different from S4 and S1 and not significantly different from S2, S4 was not significantly different from S1 and S2 but significantly different from S3. It was concluded that the addition of azolla (Azolla pinnata) at different levels to complete feed silage made from corn straw (Zea mays) did not significantly affect the calcium (Ca) content, but had a significant effect on the phosphorus (P) content. The best treatment in S3 with the addition of azolla (Azolla pinnata) 20%. Keywords: Azolla (Azolla pinnata), corn straw (Zea mays), calcium (ca) and phosphorus (p) content, complete silage

In recent years, solvate and protic ionic liquids (ILs) have attracted much attention. We synthesized both types of ILs from alkyl aza-crown ethers (L = N-propyl-1-aza-15-crown-5 (L1) and N-C6F13C2H4-1-aza-15-crown-5 (L2)). The solvate ILs [ML][Tf2N] (M = Na+, K+) were solids (Tm = 58-68 °C), whereas the solvate ILs [ML][Tf2N] (M = Li+, Ag+) and protic ILs [HL][Tf2N] were liquids with low glass transition temperatures. The ILs containing Na ions were more crystalline and exhibited higher melting points than the other ILs. The decomposition temperatures of the protic ILs were higher than those of the solvate ILs. A protic IL with a paramagnetic anion, [HL1][FeCl4] (Tm = 70.5 °C), was also synthesized and its crystal structure was determined. The solvate ILs [NaL2][X] (X = Cl-, CF3CO2-, TsO-, PhSO3-) exhibited a lower critical solution temperature (LCST)-type behavior in water. The effects of salt addition on the LCST of L2 were also investigated. The LCST of these ILs generally increased with increasing hydrophilicity or basicity of the counter anion. This tendency, which is nearly opposite to that of ILs with quaternary onium cations, is ascribed to the amphiphilic nature of the cation. The corresponding protic ILs did not exhibit LCST behavior.

Highlights An experimental machine that combined air classification and mechanical screening was investigated to separate corn grain and stover. Important variables included stover:grain ratio, air velocity, and throughput. As much as 99.4% of the grain could be separated from the stover with less than 1% foreign matter in the grain. Abstract. Corn grain and chopped stover were stored anaerobically at 37% to 50% (w.b.) aggregate moisture content to create a unique biomass feedstock. However, after storage, the two fractions must be separated to accommodate different conversion pathways. In this work, a modified cleaning system from a grain combine harvester was evaluated to investigate its effectiveness in separating the grain from the stover. While this system has been purposefully built for this task, there is no previous literature on separating grain at high material other than grain (MOG) to grain ratios. Using this system, material was separated into four fractions: Grain, Tailings, Heavy MOG, and Light MOG. Subsamples were collected, oven dried, and then hydrodynamically separated to quantify the grain content in the four fractions. Several different configurations of air velocities, mass flow rate, material MOG: grain ratios, and sieve types and openings were investigated. Grain capture was defined as the fraction of the total grain dry mass collected in the grain and tailings fractions. In five experiments, the grain capture effectiveness varied from 89.2% to 99.4% on a dry basis. The dry basis foreign matter (FM) in the clean grain was 0.6% to 10.8%. The use of a modified combine cleaning system has the potential to be one step in a system to fractionate corn grain from stover (i.e., MOG) in a biorefinery that uses both starch and cellulose as biomass feedstocks. Keywords: Air classification, Anatomical fractionation, Cleaning shoe, Corn stover, Mechanical sieving.

With South Korea’s limited capability of feed production because of its relatively small cultivable area, the country is pushed to depend on foreign feed imports despite the immensely fluctuating price of corn. Hence, intensive efforts to increase the total cultivable area in Korea like extending of farming to mountainous area is being practiced. Corn was planted in Goesan County, a mountainous area in the country. Grain and stover were harvested separately in three harvest periods: early-harvest (Aug 8), mid-harvest (Aug 18), and late-harvest (Aug 28). The nutrient composition such as dry matter (DM), crude protein (CP), crude fat (EE), organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF), and non-fibrous carbohydrates (NFC) was determined after harvest. Effective degradability (ED) of the major nutrients (DM, NDF, ADF, and CP) were measured through in vitro fermentation of rumen fluid from Hanwoo (Korean cattle). pH, ammonia-N concentration, volatile fatty acid (VFA) concentration, and gas production were periodically measured at 0, 3, 6, 12, 24, 48, and 72 h. Corn grain showed higher nutrient content and ED than stover. It also had higher gas production but its pH, ammonia-N, and total VFA concentration were lower than corn stover. The best nutrient composition of corn grain was observed in early-harvest (high CP, EE, NDF, OM, NFC, and low ADF). Early-harvest of corn grain also had high effective degradability of dry matter (EDDM), effective degradability of neutral detergent fiber (EDNDF), effective degradability of acid detergent fiber (EDADF), and total VFA concentration. On the other hand, the best nutrient composition of stover was observed in mid-harvest (high DM, CP, NDF, and low ADF). EDDM, EDNDF, and EDADF were pronounced in early-harvest and mid-harvest of stover but the latter showed high total VFA concentration. Hence, early and mid-harvested corn stover and grain in a mountainous area preserved their nutrients, which led to the effective degradation of major nutrients and high VFA production.

To investigate the effective utilization of agricultural and forestry wastes for mitigating the shortage of primary energy and environmental pollution, the pyrolysis behavior of corn straw (CS), wheat straw (WS), and poplar sawdust (PS) was studied using thermogravimetric–Fourier transform infrared (TG‐FTIR) analysis. The activation energies and pyrolysis mechanism functions of different biomass types were calculated. The results showed that the functional group structures of the gaseous products generated from the pyrolysis of different biomass types were similar, mainly including OH, aliphatic CH, CO, aromatic ring skeleton, aromatic CH, and CO groups. These functional group structures mainly existed in oxygen‐containing compounds such as phenols, ketones, aldehydes, acids, esters, alcohols, and ethers. The pyrolysis process of agricultural and forestry wastes exhibited certain differences, with the PS undergoing thermal decomposition more easily, while the thermal decomposition mechanism functions of the two agricultural wastes (CS and WS) were similar. PS had a later initial release time for volatile matter, and the oxygen compounds produced by its pyrolysis were the highest, followed by WS and CS.

Variations in fuel characteristics of corn ( Zea mays) stovers: General spatial patterns and relationships to soil properties