Feedstock For Bioenergy Production Research Articles

Bioenergy feedstock production in Chlamydomonas reinhardtii (microalgae) cultivated under mixotrophic growth with cellulose hydrolysate from agricultural waste.

In the present study, cellulose purified from finger millet agricultural waste is subjected to enzymatic hydrolysis, and the hydrolysate (predominantly glucose) is used as a carbon source supplement in the media for the mixotrophic growth of Chlamydomonas reinhardtii. Interestingly, a switch between excess starch production and excess lipid (triacylglycerols, TAG) production occurs by a small change in hydrolysate concentration in the media. Starch production increased 4.5-fold with respect to the photoautotrophic control, with a glucose concentration of 3mg/mL in the media after hydrolysate addition. This culture had TAG production enhancement by 1.5-fold. However, mixotrophic cultivation with 4mg/mL glucose concentration in the media with hydrolysate addition resulted in TAG productivity enhancement by 4.2-fold compared to control and starch amount increase of 1.3-fold. The organic carbon source (glucose) and the inorganic carbon source (citrate ions) in the hydrolysate together played a role in this delicate switching between starch and lipid pathways. Proteins, starch, and TAG molecules are analyzed in the microalgal cells grown under different conditions with FTIR spectroscopy, a rapid, high-throughput method of biomolecular estimation. High-resolution single-cell AFM studies of the cell wall structure reveal enhanced corrugations in surface morphology during mixotrophic growth with cellulose hydrolysate, illustrating an adaptive mechanism with improved mechanical stress management. Lipid droplet morphology at the single-cell level points to two distinct mechanisms of lipid accumulation: one in which the lipids are segregated as droplets, and the other in which lipid molecules are uniformly dispersed in the cytosol as unresolved, ultra-small droplets. The present study therefore analyzes both the bulk and the single-cell level changes when cellulose hydrolysate is used as a carbon source for Chlamydomonas reinhardtii mixotrophic cultivation, which serves a four-fold purpose: value from waste, fixation of atmospheric CO2, production of lipids for biodiesel, and starch for bioethanol.

Numerical Investigation on Flowability of Pulverized Biomass Using the Swelling Bed Model

Numerical investigations on the flowability of pulverized biomass are crucial for agriculture, aiding in optimizing biomass use, crop residue management, soil health improvement, and environmental impact mitigation. Rising interest in biomass and conversion processes necessitates deeper property understanding and technological process optimization. Moisture content is a key parameter influencing biomass quality. In this paper, computer simulations of shear tests depending on the moisture content using the discrete element method were carried out and compared with experimental results. An experimental study and modeling for Jenike’s direct shearing apparatus was carried out. A swelling bed model was proposed to account for the effect of moisture. The swelling bed model assumed an increase in biomass grain vorticity proportional to the moisture content. The model was solved using the discrete element method (DEM). The model considers the effect of moisture on the values of Young’s and Kirchoff’s moduli for biomass grains. The model assumed that moisture is not present in surface form, the total amount of moisture is absorbed into the interior of the material grains, and the volume of a single grain increases linearly with an increase in the volume of the absorbed moisture. The tested materials were pulverized sunflower husks, apple pomace, distiller’s dried grains with solubles (DDGS), meat and bone meal (MBM), and sawdust. Samples with moisture contents of 0%, 10%, 20%, and 30% were tested. The best agreement of the model with the experimental data was observed for the most absorbent materials in which moisture was not present in surface form, such as apple pomace, DDGS, and sawdust. Research data are important for the proper design of biomass storage, transportation equipment, and utilization as feedstock for bioenergy production or soil enrichment.

Development and utilization of genome-wide InDel markers in Sorghum [Sorghum bicolor (L.) Moench

Sorghum (Sorghum bicolor L. Moench) has become an increasingly valuable crop for food, feed, and especially bioenergy feedstock production, which makes the crop extremely attractive for studying genomics and genetic diversity. Molecular markers and genomics play essential roles in sorghum breeding. The rapid development of next-generation sequencing technology has facilitated the identification of genome-wide insertion-deletion (InDel) polymorphisms, enabling the efficient construction of InDel markers that are suitable for user-friendly PCR. This study was conducted with the objective of discovering and developing InDel markers using double digest restriction site-associated DNA sequencing (ddRAD-Seq) data. A total of 19,226 InDels distributed across 10 chromosomes in the sorghum genome was identified. Of those, deletions constituted 65.7% while the remain was insertions. A comprehensive analysis of all the chromosomes revealed a total of 80 InDel sites with a minimum length of 10 bp. For a good conversion of the InDel regions to beneficial molecular markers, specific primers were designed for the amplification of 47 InDel regions that were selected for further investigation. A diverse panel of sorghum consisting of 16 accessions served a source for the developed InDel markers validation. Of the 47 InDel markers, 14 were tested across 16 sorghum accessions and were demonstrated their helpfulness for marker-assisted selection in sorghum. The polymorphic information content (PIC) values of the 16 markers varied between 0.11 and 0.38, with an average of 0.28. The findings of this study indicated that the identification of InDels and the development of molecular markers for sorghum were accomplished using the ddRAD-Seq data.

Water Hyacinth (Eichhornia crassipes) As a Possible Alternative Energy Source: A Case Study for INSEE Cement Manufacturing Plant in Puttalam, Sri Lanka

Cement manufacturing is typically energy-intensive process and currently using alternative fuels partially or totally to replace fossil fuels to reduce the energy and environmental costs. Biomass is one of the main alternative fuel utilized by the cement industry with the potential to replace up to 20% of total energy demand. Water hyacinth (WH) is a problematic invasive alien species in aquatic ecosystems of all climatic zones in Sri Lanka. Because of it is non-edible, rapid growth, and freely available in larger quantities, WH has the potential to be used as biomass energy. Several countries have been studied for WH as feedstock for bioenergy production while physical and chemical composition of WH biomass has been tested by many researchers. However, biomass physiochemical properties may be varied by different place and conditions and there is no significant study for industrial application of WH biomass to burn in cement plant kiln as alternative energy source. Thus, this study aimed to elucidate the potential of WH biomass as an alternative energy source for the INSEE cement plant in Puttalam. The study was conducted in three selected reservoirs namely, Tabbowa reservoir (TR), Murukkuwatawana reservoir (MR), and Nawadankulama reservoir (NR) located in Puttalam district Northwestern province of Sri Lanka. The quantity of fresh and dry WH biomass was estimated with the WH covered area and fresh and dry weights of WH in unit area.WH covered area of in each reservoir during 2020 and 2021 was digitized directly in Google earth satellite images using Google Earth Pro software with help of visual interpretation techniques. WH biomass per unit area were measured by the subjective sampling method. WH samples from each reservoir were collected for analyzing biomass, and to determine the fuel characteristics such as net calorific value (NCV), Chlorine and Sulfur content, moisture, volatile matter, fixed carbon, and ash content. According to the results, the fresh WH biomass was recorded as 692.62, 389.85, 23.58 tons in 2020 and 3570.82, 584.53, 33.31 tons in 2021 in the TR, MR, and NR respectively, while the dry WH biomass was recorded as 41.65, 24.65, 1.31 tons in 2020 and 214.74, 36.96, 1.85 tons in 2021 in the TR, MR, and NR respectively. NCV of the WH composite sample was 12.02 MJ/kg. Moisture content, ash content, chlorine and sulfur content were recorded as 13.56%, 10.95%, 1.06%, and 0.14% respectively. Except for chlorine content, other parameters agreed with the acceptable limits for using WH as an alternative energy source for cement industry. To replace 1 ton of coal, 2.2 tons of dry WH were required from 35 tons of fresh WH biomass while to produce 1 ton of clinker, 0.32 tons of dry WH were required from 5.2 tons of fresh WH biomass. Since relatively large quantities are freely available and with high volatile content and calorific value, WH is suitable as an alternative energy source for cement industry. However, economic feasibility should be studied prior to the commercial application.
 Keywords: Alternative fuel, Biomass, Water hyacinth, Calorific value

Chemical Composition of the Aboveground Tissues of Miscanthus × giganteus and Relationships to Soil Characteristics

AbstractTo reduce the C footprint of human activities, there is a growing need for alternative energy sources including the production of bioenergy feedstocks. Miscanthus × giganteus is a high yielding grass with low environmental impact and high potential for feedstock use. Studying the composition of the aboveground tissues of Miscanthus is important for understanding feedstock quality for biofuel conversion and how crop residue quality may affect soil input management. Data on Miscanthus leaf and stem chemistry including carbon (C), nitrogen (N), macronutrient concentrations, and the optical characteristics of the water extractable organic matter (WEOM) was analyzed to identify differences in composition between aboveground tissues and modeled to identify soil variables that may be correlated with tissue chemistry. Leaves and stems were dominated by N, potassium (K), calcium (Ca), phosphorus (P), and magnesium (Mg), but overall, the leaves contained higher nutrient concentrations compared to the stems. The leaves displayed elevated Si:K (0.0935) and Ca:K (0.445) ratios and lower C:N (36) and C:P (323) ratios compared to the stems (0.0560, 0.145, 150, and 645, respectively). Leaf WEOM contained large, aromatic, and complex structures, while the stem WEOM was dominated by small, recently produced structures. Varying relationships were found between tissue C and the mobile C pool in surface (0–15 cm) and deep (45–60 cm) soils. Overall, Miscanthus leaves had a chemical composition indicative of reduced biofuel quality compared to the stems. The relationships with soil mobile C suggest a dynamic linkage between Miscanthus physiology and this active soil C pool. These results have implications for crop nutrient allocation and nutrient management practices.

Buriti (Mauritia flexuosa L.) wastes as potential lignocellulosic feedstock for bioenergy production: Physicochemical properties, thermal behavior, and emission factors

Biomass is one of the most feasible renewable alternatives to fossil fuels. Given this fact, this study aims to demonstrate that buriti fruit wastes (pits and husks) are a promising new feedstock for bioenergy production via thermochemical conversion. To evaluate the suitability of buriti pits and husks for bioenergy generation, their physicochemical properties, performance indices, and pyrolytic behavior were evaluated based on ultimate, proximate, and calorimetry analyses, emission factors, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM images), energy dispersive spectrometry (EDS), thermal analysis (TG/DTG/DSC curves), and devolatilization index (DI). In addition, the mineral and metal contents were quantified by inductively coupled plasma optical emission spectroscopy (ICP-OES). The buriti wastes exhibited low ash (< 3.2%) and moisture contents (< 13.0%), a high heating value (HHV) of 16.11–20.61 MJ kg−1, negligible nitrogen content (< 1.2%) and sulfur (non-detected), and lower carbon dioxide (1236–1244 g kg−1) and nitrogen oxides (3.32–3.95 g kg−1) emission factors than those of reference fuels. The physicochemical properties of buriti pits and husks were consistent with those of other agroforestry and agroindustrial biomasses. The DI of 1.47 and 5.27 × 10−8 mg min−1 °C−3 (or 0.35 and 1.17 ×10−6% min−1 °C−3) of buriti pits and husks, respectively, revealed the main difference between the thermal performance and suitability of buriti pits and husks for the partial or total replacement of fossil fuels. The buriti wastes displayed exceptional performance under direct combustion, and a comparison of buriti pits and husks highlighted the remarkable suitability of buriti pits for pyrolysis, probably due to the oleaginous nature of the material.

Study on biofuel efficiency of tropical banana leaf biomass using spectroscopy, kinetic and thermodynamic parameters

Bio-oils and biochar are some of the valuable products, which are usually harnessed through the pyrolysis process. Under the current investigation, three popular edible banana species were subjected to the pyrolysis process in order to decipher their bioenergy potential. Thermo-gravimetric analysis was utilized to determine the kinetic parameters. The levels of Eα were estimated to be 206 kJ/mol for Musa acuminata, 179 kJ/mol Musa chinichampa and 180 kJ/mol for Musa paradisiaca. Values of A in the range of 1012–1015 s−1, 1012–1015 s−1,1013–1015 s-1, and 1013–1015 s−1 were observed under FWO, KAS, Starink, and Tang model, respectively. From the master plot analysis, it was observed that the reaction mechanism involved in the thermal decay of major cell wall polymers was quite complex and followed a multi-step reaction mechanism. Analysis of the thermodynamic parameters, validated the endothermic nature of pyrolysis. Overall, combined with the different physical and chemical characteristics, it is observed that the leaf biomass of tropical banana species Musa chinichampa is a better feed stock for bioenergy production.

Eastern red cedar effects on carbon sequestration and soil quality in the Great Plains

AbstractEastern red cedar (ERC, Juniperus virginiana L.) is a common tree species in agroforestry plantings and has great potential for bioenergy production due to physical and chemical characteristics of its biomass. The objective of this study was to assess the effects of ERC plantings on carbon (C) sequestration and selected soil quality parameters in existing plantings across the northern U.S. Great Plains. Nine locations were selected in five states with mean annual precipitation (MAP) from 446 to 999 mm and mean annual temperature (MAT) from 4.4 to 10.0°C. Infiltration was measured using the twin ring technique at nine sites in each tree planting and adjacent field (crop, pasture, or hay) at each location. Following infiltration measurements, a 4.8 cm‐diameter soil core to 30 cm depth was collected from inside one infiltration ring of each pair for bulk density, pH, aggregate stability, soil organic carbon (SOC), and total nitrogen (TN) analyses. Penetration resistance in 2.5 cm increments to 30 cm depth was measured in the other infiltration ring. SOC stocks under ERC were significantly higher than in the adjacent field soil at five of the locations and, for all locations, averaged 16.8% greater than in the adjacent field. The estimated SOC accumulation rate for the eight locations with uniform tree stand age averaged 0.30 Mg C ha−1 year−1. Most locations had higher TN and C/N and lower bulk density beneath ERC. Fewer differences for infiltration and penetration resistance and smaller and less consistent differences for pH and aggregate stability were observed. Tree aboveground C stocks were estimated to increase an average of 2.05 Mg C ha−1 year−1. Estimated tree aboveground biomass C and SOC stocks under ERC and in adjacent fields were strongly correlated with MAP. Potential ERC planting for C sequestration or bioenergy feedstock production is not likely to significantly degrade soil quality and may improve soil physical or chemical quality for locations in the US Great Plains.

Mixotrophic growth regime of novel strain Scenedesmus sp. DDVG I in municipal wastewater for concomitant bioremediation and valorization of biomass

Availability of cost-effective nutrients for the commercial cultivation of microalgae is one of the major challenges. The present study investigated the feasibility of primary municipal wastewater (PMWW) collected from a local wastewater treatment plant in Minnesota, USA as an alternative to fresh-water microalgae growth media towards high-value bioenergy feedstock production. The novel strain Scenedesmus sp. DDVG I was cultivated in the PMWW under heterotrophic and mixotrophic modes in 250 mL Erlenmeyer flasks. The optimized cultivation mode was further scaled up to the 3-L bubbled bioreactor. The study confirmed the wastewater as a potential growth medium while Scenedesmus sp. DDVG I showed superior biomass productivity (0.069 g/L d), lipid yield (22.5%), and FAME content (22.04% in dry cell weight) over 10 days in the mixotrophic mode. The biomass also showed high essential amino acid content (159.8 mg/g DCW). The corresponding values for bioremediation efficiencies of chemical oxygen demand (COD) and total nitrogen (TN) by Scenedesmus sp. were 75.6% and 99.8% respectively. Meanwhile, ammonia nitrogen (NH3–N) and total phosphorus (TP) were removed at up to 100% removal efficiencies. Analyses of fatty acid profile and different parameters that were required for biodiesel characterization revealed the high-quality nature of the Scenedesmus-derived oil. Overall, the study concluded effective bioremediation of municipal wastewater by Scenedesmus sp. DDVG I with the recovery of valuable resources from the biomass.

Utilization of Grassy Biomass Grown in Heavy-Metal Contaminated Soil as Feedstock for Bioenergy Production - An LCA Study

Biomass is the only renewable source of carbon that, when utilized efficiently and optimally, can significantly help to reduce our reliance on fossil fuels. Certain types of perennial grasses, such as switchgrass, have great potential to be used as bio-renewable feedstock to produce bioenergy due to their relatively high yields of biomass per acreage of land. Furthermore, these grasses have the capability of extracting heavy metals from the contaminated soil, which in turn can improve the quality of the soil. A biorefinery process system consisting of two hydrolysis steps and a fast pyrolysis step to produce sugars and bio-oil using switchgrass grown in lead contaminated soil was studied. The study showed that the presence of lead in the grassy feedstock did not seem to affect the yields of sugars and bio-oil from the hydrolysis and the fast pyrolysis steps, respectively. An LCA study on growing switchgrass for soil phytoremediation using the switchgrass as feedstock for the biorefinery system was performed. Results from the study showed that the combination of using switchgrass as soil phytoremediation agent and feedstock for producing energy in a biorefinery decreases GHG emissions and lowers the use of energy produced from fossil fuels when compared with a combination of a refinery system and ex-situ excavation for soil remediation.

Mapping QTLs for spring green-up, plant vigor, and plant biomass in two lowland switchgrass populations.

The online version contains supplementary material available at 10.1007/s11032-022-01296-7.

Phycoremediation of milk processing wastewater and lipid-rich biomass production using Chlorella vulgaris under continuous batch system

This study compiles the results of phycoremediation of milk processing wastewater (MPWW) and production of lipid-rich Chlorella vulgaris biomass using a continuous batch system operated for 12-wks. After a 4-wks interval, a new MPWW was loaded photobioreactor to provide appropriate nutrient supply to algae. Results indicated that MPWW supported the algal growth efficiently and the maximum algal growth was recorded in the ranges of 400.36 to 421.58 mg L−1 during 4-wk's of the cultivation cycle. Average reduction in total nitrogen, TN (45.82–69.18%); nitrate, NO3 (93.32–94.54%); total ammonium nitrogen, TAN (92.94–94.54%); sulphate, SO4−2 (85.13–87.34%); total phosphorus (75.09–78.78%); and biochemical oxygen demands, BOD (89.53–92.40%) was recorded during 12-wks phycoremediation of MPWW. Harvested algal biomass (dry weight basis, DW) exhibited a significant content of total sugar (45.5%) and total lipid (39.7%). The lipid profiling results indicated the presence of palmitic acid (39.9%), oleic acid (21.08%), linoleic acid (13.13%), and other C18 compounds in algal biomass, suggesting the suitability of MPWW for Chlorella vulgaris cultivations. Algal biomass exhibited a high heating value (MJ/Kg of DW) in the range of 17.3 to 25.1, comparable to other lignocellulose biomass to be used for bioenergy purposes. Results of this study indicate that MPWW could be utilized as a valuable medium for Chlorella vulgaris cultivation under a circular economy approach: wastewater treatment and bioenergy feedstock production. The effect of controlled environmental conditions on algal growth behavior and lipid composition in biomass, while using MPWW as a medium, could be investigated in future studies.

Aerial Imagery Can Detect Nitrogen Fertilizer Effects on Biomass and Stand Health of Miscanthus × giganteus

Miscanthus × giganteus (Miscanthus) is a warm-season perennial grass grown for bioenergy feedstock production. Nitrogen (N) fertilizer management is crucial for the sustainability of Miscanthus production. In our two-year study (2018 and 2019), we investigated the role of vegetation indices (VIs) in evaluating N fertilization (0 N, 56 N, 112 N, and 168 N kg ha−1) impacts on Miscanthus biomass yield and stand health. The flight campaigns were conducted early, middle, and late during the summer growing season. Among the VIs, mid-summer growing season NDRE provided the best prediction of fresh biomass (R2 = 0.87 and 0.97) and dry biomass (R2 = 0.89 and 0.97) in 2018 and 2019, respectively. The VIs generally showed that it was possible to distinguish between 0 N and 168 N treatments, but neither 0 N and 56 N kg ha−1 nor 112 N and 168 N kg ha−1 could be separated. The results from this study highlight the importance of moderate application of N (112 kg N ha−1) in improving and maintaining the stand health and biomass yield of Miscanthus over time and suggest that mid-summer growing season VIs, NDRE in particular, can be useful for assessment of Miscanthus stand health and biomass yield.

Submerged hollow-fiber-ultrafiltration for harvesting microalgae used for bioremediation of a secondary wastewater

Microalgae were employed to remove nutrients from a pre-treated wastewater (so-called anaerobic membrane bioreactor effluent, AnMBR effluent) over a 24-day semi-continuous cultivation with varied N:P ratios. NH4+-N reduction percentage ranged from 68 to 94% with average removal rates varying from 8 to 26mgN·L-1d-1 at different stages. Total phosphorus was almost completely removed shortly after inoculation. Biomass productivity ranged from 0.13 to 0.19 g·L-1d-1 during the cultivation. A submerged membrane-based filtration device was used to investigate the formation of biofouling, which occurred on the membrane surface during filtration and is considered as a bottleneck in downstream processing. Results indicated most severe fouling was caused by original microalgal suspension, compared to its individual fractions (cellular resuspensions, supernatant and AnMBR effluent). Irreversible fouling mainly occurred at the beginning of the filtration process; extracellular organic matter and cellular debris in the supernatant changed the fouling behavior more significantly than morphological properties of the algae cells; AnMBR effluent also led to a nonnegligible fouling effect. To minimize biofouling, TOC content in wastewater should be carefully controlled before and during cultivation. The current membrane can be proposed for long-term filtration, as irreversible fouling only occurred at the beginning and reversible fouling can be controlled effectively by backflushing and aeration. The biomass, characterized by relatively high protein and carbohydrate but low heavy metal content, indicated its potential as feeds and feedstock for bioenergy production. The present work provides novel insights into the coupling of wastewater treatment and fouling control, which has been rarely studied.

Accumulation of biomass and lignocellulosic compounds in photoperiod-sensitive biomass sorghum genotypes

Biomass sorghum [Sorghum bicolor (L.) Moench] has unique characteristics that allow its use as a feedstock for bioenergy production. This study aimed to analyse the growth and accumulation of biomass and lignocellulosic compounds in photoperiod-sensitive biomass sorghum genotypes and to evaluate interactions with the environment at different phenological stages using the absolute and relative crop growth rates. Four photoperiod-sensitive biomass sorghum genotypes were evaluated over two crop years and two sites in the state of Minas Gerais, Brazil. It was mensured agronomic and technological traits. The mean performance of the genotypes were adjusted using logistic and polynomial regression models, and the absolute (CGR) and relative (RCGR) growth rates were subsequently estimated. The environment (site and/or crop year) influenced the trait expression regarding plant height, cellulose and lignin accumulation. The genotypes at Sete Lagoas site matured earlier, with a greater plant height and greater accumulation of biomass and lignocellulosic compounds, except lignin, over a shorter period compared to Lavras site. Across genotypes and environments, CGRs with a peak inflection at approximately 90 days after sowing (DAS) were observed for growth and biomass production, but a decrease starting at 30 DAS was observed in the CGRs for lignocellulosic compounds and in the RCGRs for growth, biomass production and lignocellulosic compounds. In addition, at both sites, the crop could be harvested earlier, at approximately 120 DAS in Sete Lagoas and 150 DAS in Lavras, given the high biomass production, dry matter percentage above 30% and high content of lignocellulosic compounds.

Intra‐ and inter‐annual variability of nitrification in the rhizosphere of field‐grown bioenergy sorghum

AbstractBiological nitrification inhibition (BNI) and plant–microbe competition for ammonium (NH4+) by sorghum (Sorghum bicolor(L.) Moench) have the potential to suppress nitrification, reducing nitrate (NO3−) and nitrous oxide (N2O) production for more sustainable bioenergy feedstock production. However, it is unknown how variability in environmental factors, field management, and plant growth affect the suppression of nitrification. We conducted a field trial with four genotypes of energy sorghum and four fertilization rates in central Illinois, USA, and measured soil N pools, potential nitrification and denitrification rates, and microbial community composition in bulk and rhizosphere soils to assess nitrification suppression throughout the 2018 and 2019 growing seasons. Concentrations of NO3−and NH4+were very low in rhizosphere soil regardless of fertilization level, suggesting strong N demand by plants and microbes. Potential nitrification was lower in the rhizosphere soil than bulk soil, and this suppression was strongest mid‐season ~2 months after planting in both years (20% suppression in 2018 and 58% in 2019). Since precipitation was lower during the mid‐growing season of 2019 compared to 2018, we speculate that hydrophilic BNI root exudates accumulated in the rhizosphere and suppressed nitrification more than in 2018 when soil moisture was higher. Unfertilized plots had greater nitrification suppression than fertilized plots during the mid‐season in 2018, but otherwise nitrification suppression was insensitive to fertilizer treatment. Potential denitrification was stimulated in the rhizosphere compared to bulk soil in both study years, suggesting that heterotrophic activity was stimulated by plant carbon inputs, possibly further suppressing slower‐growing chemoautotrophic nitrifying microbes. Overall, we found inter‐ and intra‐annual variation in nitrification suppression in the rhizosphere of field‐grown biomass sorghum, suggesting that plant phenology and environmental conditions should be considered when devising strategies to improve the nitrogen sustainability of this annual bioenergy crop.

Pyrolytic thermal degradation kinetics of pigeon pea stalk (Cajanus Cajan): Determination of kinetic and thermodynamic parameters

This article highlights the pyrolytic thermal degradation behavior of pigeon pea stalk (PPS) at different heating rates (β) ranging from 10 to 40 °C/min in inert nitrogenous atmosphere using the thermogravimetric analysis (TGA). Three isoconversional methods: Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Starink method were used to evaluate the kinetic parameters, including activation energy (Ea) and pre-exponential factor for range of conversion degree (α) 0.1 to 0.9. The highest average value of activation energy for PPS was found 126.24kJmol−1 for FWO method followed by Starink and KAS method as 122.59kJmol −1 and 116.23kJmol −1 respectively. Pre exponential factor (A) and thermodynamic parameters such as change in Gibbs free energy (G), enthalpy (ΔH) and entropy (ΔS) were computed and critically discussed. The average value of ΔH was found as 117.36, 110.95 and 120.97kJmol −1 for FWO, KAS and Starink method, respectively. Whereas, ΔG values were noticed very close to each other (ranges from 302 to 315kJmol −1) and average values of ΔS were − 181, −192 and −185Jmol−1K−1 for OFW, KAS and Starink method, respectively. The difference between average activation energy and value of ΔH was noticed imperceptible (∼5kJmol −1), which is a positive confirmation about the generation of green product from PPS requiring low energy potential. As summary PPS was found to have significant potential to be used as a feedstock for bioenergy production.

Alteration of The Properties of Spent Eucalyptus Biomass from Steam Distillation

Steam distillation is a common method to extract the eucalyptus oil from eucalyptus biomass. The spent biomass of the steam distillation process could be used as biofuel feedstock. This study aims to investigate the effect of eucalyptus biomass steam distillation time on the alteration of the spent biomass. The properties studied include carbon retention, fuel properties namely proximate and ultimate analyses as well as grindability. Those properties were investigated from 5 to 180 minutes of the distillation time. The grindability and fuels chemistry of spent biomass were little affected by the steam distillation process. The results show that to use the spent biomass of steam distillation as a feedstock for bioenergy production it is quite promising.

Oil Palm Empty Fruit Bunch as a Potential Feedstock for Composting

Oil palm plantation has been widely planted in tropical countries, particularly Malaysia. Oil palm biomasses as by-products of palm oil production, therefore, exist abundantly. Four kilograms of dry biomasses are generated for every kilogram of palm oil produced. Empty fruit bunch is a major solid waste produced by palm oil mills, constituting 23% of the total weight of the fresh palm fruit bunch. As one of the largest palm oil producers, Malaysia generated a huge amount of EFB annually, making the country's disposal process a headache issue. Therefore, utilizing these wastes strategically could be beneficial from both economic and environmental points of view. Ideally, EFB could be used as feedstocks for bioenergy production, composites fabrication, activated carbon, and chemical synthesis. Apart from that, composting is also one of the potential approaches to solving this waste's abundance. Composting oil palm EFB means converting the EFB waste, which is essentially organic in nature, into humus suitable for crop production. The main purpose of composting is to handle organic wastes and enhance soil fertility safely. This paper gives an overview of the latest status and technologies dealing with composting of oil palm EFB, its limitations, current issues, and way forward.

Site and Bioenergy Cropping System Similarly Affect Distinct Live and Total Soil Microbial Communities.

Bioenergy crops are a promising energy alternative to fossil fuels. During bioenergy feedstock production, crop inputs shape the composition of soil microbial communities, which in turn influences nutrient cycling and plant productivity. In addition to cropping inputs, site characteristics (e.g., soil texture, climate) influence bacterial and fungal communities. We explored the response of soil microorganisms to bioenergy cropping system (switchgrass vs. maize) and site (sandy loam vs. silty loam) within two long-term experimental research stations. The live and total microbial community membership was investigated using 16S and ITS amplicon sequencing of soil RNA and DNA. For both nucleic acid types, we expected fungi and prokaryotes to be differentially impacted by crop and site due their dissimilar life strategies. We also expected live communities to be more strongly affected by site and crop than the total communities due to a sensitivity to recent stimuli. Instead, we found that prokaryotic and fungal community composition was primarily driven by site with a secondary crop effect, highlighting the importance of soil texture and fertility in shaping both communities. Specific highly abundant prokaryotic and fungal taxa within live communities were indicative of site and cropping systems, providing insight into treatment-specific, agriculturally relevant microbial taxa that were obscured within total community profiles. Within live prokaryote communities, predatory Myxobacteria spp. were largely indicative of silty and switchgrass communities. Within live fungal communities, Glomeromycota spp. were solely indicative of switchgrass soils, while a few very abundant Mortierellomycota spp. were indicative of silty soils. Site and cropping system had distinct effects on the live and total communities reflecting selection forces of plant inputs and environmental conditions over time. Comparisons between RNA and DNA communities uncovered live members obscured within the total community as well as members of the relic DNA pool. The associations between live communities and relic DNA are a product of the intimate relationship between the ephemeral responses of the live community and the accumulation of DNA within necromass that contributes to soil organic matter, and in turn shapes soil microbial dynamics.