Search NASA⌕ Search

SEARCH · Search NASA

Results for “Biomass Yield”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Production of Biocrude in an Advanced Photobioreactor-Based Biorefinery

Algenol Biotech, the National Renewable Energy Laboratory (NREL), Georgia Institute of Technology, Arizona State University, and Reliance Industries formed a team to advance the state of the art in algal biomass production and downstream processing technologies, with the end goal of a sustainable, economically viable biofuel intermediate (BFI, biocrude) product. The project included examination of high value co-product production as a market entry strategy and for enhancing the economics of a biorefinery for BFI production. The project targeted innovations in biology, operations, and engineering. The goals of the project were: BFI productivity greater than 4,000 gal-BFI/acre-yr on an annualized basis; energy efficient innovations in downstream operations resulting in an energy expenditure less than 10% of the BFI energy content and a carbon footprint reduction of more than 60% compared to fossil alternatives; and a comprehensive Techno-Economic Analysis (TEA) that identifies limiting factors for commercial viability of a photobioreactor (PBR)-based biofuel product. The project achieved the overall objectives. Strain development efforts led to the identification of a strain (Cyanobacterium sp. AB1166) that, relative to the previous best strain (Cyanobacterium sp. AB1), exhibited a ~10% increase in productivity under commercially-relevant cultivation conditions and also resulted in cultures with a >50% reduction in viscosity such that harvesting efficiency was improved; these results represent achievement of key project milestones. Progress was also made at NREL in altering the biochemical composition of algal biomass to improve the yield of BFI produced via HTL. These strain enhancements coupled with improved outdoor cultivation practices, including semi-continuous operation, increased areal biomass productivity by nearly 80% over the established baseline productivity. The annualized productivity achieved (26.8 g/m2-d), paired with HTL conversion yields realized at NREL and RIL (38% ± 2% BFI), translates to 4,100 gal-BFI/acre-yr, exceeding the FY20 BETO goal of 3,700 gal-BFI/acre-yr. Significant progress was also demonstrated in large scale PBR-based production system design, operability, and cost reduction. A 24,000-L production module comprised of 240 interlinked PBRs was constructed and successfully operated outdoors for over one year in Fort Myers, Florida. Aided by a state-of-the-art productivity model, the productivities achieved convincingly demonstrated scalability of laboratory results determined at the mL to L scale to large-scale outdoor operations exceeding 20,000 L. The system was used to cultivate Arthrospira platensis (Spirulina), an industrially-relevant cyanobacterium and source for phycocyanin, an approved blue food colorant that Algenol is developing as a risk reduction strategy for future biofuel projects and as a potential business opportunity. A key project milestone to develop phycocyanin extraction and purification technologies was achieved ahead of schedule, and product samples received positive feedback from potential customers. The production and downstream operations data generated in this project were used to conduct and refine Techno-Economic and Life Cycle Assessments to provide research guidance for reducing the costs and environmental footprint of algal biofuel and co-product manufacturing plants. Several CO 2 supply scenarios for an algal biorefinery were identified as being capable of providing a large (>60%) reduction in carbon footprint in comparison to gasoline. The TEA assessments incorporated detailed comparisons of PBR versus open pond production systems, yielding a 3-fold higher areal productivity for PBRs and suggesting overall production cost parity for the two systems. The progress in this ABY2 project addressed many of the the barriers identified for the Advanced Algal Systems R&D Program and are directly relevant to achieving the established BETO goals associated with large scale biofuel production and cost reduction.

09 BIOMASS FUELS↗
DOE OSTI2026

Forest aboveground biomass estimation through integration of sentinel-2 and PALSAR-2 time series: assessing models trained on GEDI and field inventory benchmarks

Accurate and spatially explicit forest Aboveground Biomass (AGB) mapping through remote sensing is critical for quantifying terrestrial carbon stocks and informing effective forest management strategies. However, AGB estimation in dense forests with complex terrain remains challenging due to satellite sensor signal saturation problem (saturation issue occurs in high biomass forests), structural complexity, and limited ground truth for calibration. This study presents a novel framework that integrates multi-temporal Sentinel-2 optical imagery, ALOS PALSAR-2 Synthetic Aperture Radar (SAR) data, and topographic variables with explainable Machine Learning to map AGB across mountainous forests within subtropical and temperate oceanic climate zones of Mexico. We evaluate the effects of temporal granularity and sensor synergy by comparing multiple temporal inputs and sensor configurations (Sentinel-2, PALSAR-2, and their fusion), and assess model performance using two reference datasets: NASA GEDI LiDAR-derived biomass and Mexico’s National Forest and Soil Inventory (INFyS). Our results showed that models trained on INFyS consistently outperformed those trained on GEDI, highlighting limitations in GEDI’s reliability in biomass estimates within this study region. Furthermore, the integration of Sentinel-2 and PALSAR-2 provided improved predictions compared to single-sensor models, particularly when combined with temporally explicit yearly statistics. The best-performing model, which was trained on INFyS data, and considered both Sentinel-2 and PALSAR-2 yearly statistics, as well as topographic variables, achieved an R2 of 0.64, RMSE of 51.10 Mg/ha, and relative RMSE (rRMSE) of 58.69%. Explainable ML analysis identified Sentinel-2 spectral indices and topographic features as key predictors, while PALSAR-2 metrics provided complementary information, partially mitigating saturation effects in high-biomass areas. Specifically, integrating both sensors substantially improved AGB estimation in high biomass forest (≥200 Mg/ha), yielding 98% gains over optical-only model, with resulting estimates exceeding GEDI L4B by 29% and ESA-CCI-BIOMASS by 174%. Terrain-stratified analysis indicated close agreement with GEDI in low-slope areas, with increasing divergence as slope steepness increased, while estimates remained consistently higher than ESA-CCI-BIOMASS across all slope classes. The proposed approach advances multi-sensor fusion and temporal feature engineering for AGB mapping using open-access satellite datasets, providing a scalable and reproducible framework for annual biomass monitoring in topographically complex mountainous forests. The resulting 25 m resolution biomass product has the potential to provide spatially detailed information for forest monitoring and may support applications in carbon accounting and forest management.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Understanding the Effects of Ash Content on Various Pretreatment Technologies for the Bioconversion of Corn Stover

Here, the study aimed to examine the effects of adding biomass ash on the biochemical processes involved in fermentable sugar production. Corn stover was pretreated using several methods—hot water, dilute acid, alkaline, γ-valerolactone, and ionic liquid methods, each examined with ash loadings of 7.18% and 21.07%. The findings demonstrated that increased ash content adversely affected both pretreatment and enzymatic hydrolysis. Specifically, the total sugar yield was 3 to 16% lower at the higher ash content across all pretreatment methods, and up to 4.01% lower during enzymatic hydrolysis. For acidic pretreatment, the sugar yield decreased as ash content increased. In contrast, ash content had a lesser impact on alkaline pretreatment compared to acidic pretreatment. For example, using corn stover with an ash content as high as 22.65% resulted in only a 2.90% decrease in total sugar yield compared to corn stover without added ash. Further, the primary reasons for the reduced sugar yield in higher ash biomass during acidic pretreatments were likely the neutralizing effect of the ash and decreased acid access to the substrates. During enzymatic hydrolysis, ash reduced the sugar yield by limiting enzyme access to cellulose.

09 BIOMASS FUELS↗
NASA NTRS2003

Carbon balance in bioregenerative life support systems: some effects of system closure, waste management, and crop harvest index

In Advanced Life Support (ALS) systems with bioregenerative components, plant photosynthesis would be used to produce O2 and food, while removing CO2. Much of the plant biomass would be inedible and hence must be considered in waste management. This waste could be oxidized (e.g., incinerated or aerobically digested) to resupply CO2 to the plants, but this would not be needed unless the system were highly closed with regard to food. For example, in a partially closed system where some of the food is grown and some is imported, CO2 from oxidized waste when combined with crew and microbial respiration could exceed the CO2 removal capability of the plants. Moreover, it would consume some O2 produced from photosynthesis that could have been used by the crew. For partially closed systems it would be more appropriate to store or find other uses for the inedible biomass and excess carbon, such as generating soils or growing woody plants (e.g., dwarf fruit trees). Regardless of system closure, high harvest crops (i.e., crops with a high edible to total biomass ratio) would increase food production per unit area and O2 yields for systems where waste biomass is oxidized to recycle CO2. Such interlinking effects between the plants and waste treatment strategies point out the importance of oxidizing only that amount of waste needed to optimize system performance. Published by Elsevier Science Ltd on behalf of COSPAR.

NASA Discipline Life Support Systems↗
DOE OSTI2026

Optimization of pre-commercial enzyme dosage for a potential lignocellulosic biorefinery

Lignocellulolytic enzymes remain one of the primary cost constraints in second-generation (2G) ethanol biorefineries. Achieving efficient hydrolysis of structural carbohydrates with minimal enzyme dosage, maintaining slurry fermentability for industrially relevant ethanol titers, and maximizing ethanol yield per ton of biomass are among the major challenges in 2G processes. In this study, we optimized the dosages of pre-commercial cellulase (NS22257) and hemicellulase (NS22244) on pilot-scale, hydrothermally pretreated lignocellulosic substrates. Enzyme dosages were evaluated at three levels: 20 mg of cellulase with 7.25 mg of hemicellulase (ED-1), 40 mg with 14.5 mg (ED-2), and 60 mg with 21.75 mg (ED-3). As expected, the highest sugar yields were obtained with ED-3; however, for sweet sorghum, oilcane, and miscanthus, sugar yields from ED-2 and ED-3 were not significantly different ( p < 0.05). For example, sweet sorghum produced 123.78 ± 1.54 g L −1 and 125.76 ± 0.46 g L −1 of total sugars (glucose and xylose) with ED-2 and ED-3, respectively. Although energycane exhibited a statistically significant difference between ED-2 and ED-3, the incremental gain with ED-3 was modest, increasing sugar release by only 9.02 g L −1 relative to ED-2. Importantly, ED-1 resulted in sugar yields of 88.88 ± 3.64 to 106.86 ± 1.21 g L −1 , sufficient to achieve ethanol titers ≥40 g L −1 , the threshold required for industrial relevance. A semi-integrated bioprocess validated this outcome, producing 42.09 ± 2.38 g L −1 ethanol and an estimated yield of 213.38 L of ethanol per dry ton of pretreated biomass, requiring only 20.83 L of cellulase and 6.25 L of hemicellulase per ton. Remarkably, these enzyme dosages were approximately tenfold lower than those reported in prior studies.

Deshavath, Narendra Naik [Univ. of Illinois at Urb↗
DOE OSTI2023

Enzyme-assisted liquefaction for different fractions of corn stover pellets

With an increase in population, the world will depend on renewable sources to meet the increasing energy needs. The use of lignocellulosic biomass as a renewable source has been proven efficient for conversion to cellulosic ethanol and capable of contributing to thresholds for energy demand while reducing greenhouse gases by 90% when compared with fossil fuels. However, limitations in feeding and flow within biorefineries are encountered when system plugging occurs due to biomass compaction and a high yield stress for slurries formed during its processing. Furthermore, differences in the biomass source present a challenge to the continuity of operations and reliability in the process. This work explores enzyme-assisted liquefaction for solid loadings up to 30% as an alternative for the creation of slurry from two different types of biomass (pelleted corn stover and cobs) that were liquefied in a fed-batch process using commercial enzymes Celluclast 1.5L or Ctec-2 at 1FPU/g or 3 FPU/g of dry solids in a 10 mM sodium citrate buffer solution (pH 4.8). Pellets were fed into a 1 L stirred bioreactor according to a predefined fed-batch protocol during the first 5 hours until 30% solid loading was reached. After 6, 24 and 96 hours, samples were taken and characterized with respect to their composition, rheology, and water absorption. Successful slurry creation with dramatically reduced yield stress was achieved for corn stover for both enzymes assessed. Yield stresses of 178±7 Pa (3 FPU, Celluclast 1.5L) and 79±6 Pa (3 FPU, Ctec-2) were measured for corn stover at 24 hours, compared to 6,000 Pa for samples without enzyme. Yield stress was 155± 29 Pa (3FPU, Ctec-2) and 257 ± 72 Pa (1 FPU, Celluclast 1.5L) for corn cobs at 24 hours. A profile for 6, 24 and 96h of yield stress measurements and sugar conversion is presented.

Gutierrez, Diana↗
DOE OSTI2024

Sustainable strategies to achieve industrial ethanol titers from different bioenergy feedstocks: scale-up approach for better ethanol yield

Hydrothermal pretreatment is a promising approach to lignocellulosic biomass processing for enzymatic hydrolysis and high-yield bioethanol fermentation, as it reduces downstream inhibitor content and the amount of toxic byproducts generated. In this paper, the ethanol yield and productivity of an engineered xylose-fermenting strain of Saccharomyces cerevisiae were tested on lignocellulosic hydrolysates produced with varying citrate buffer concentration, solid loading, supplemental nitrogen source, and feedstock of origin, and a semi-integrated bioprocess which integrates enzymatic hydrolysis and bioethanol fermentation was developed. The greatest ethanol yields (g p /g s ) of 0.490 ± 0.008, 0.460 ± 0.001, 0.420 ± 0.002 and 0.410 ± 0.002 were obtained from bioenergy sorghum (BES), Miscanthus × giganteus (MG), energy cane (EC), and oilcane (OC), respectively. In addition, an equivalent of 291 L, 253.54 L, 257.8 L, and 260.3 L of bioethanol were produced per ton of BES, MG, EC, and OC, respectively, by using urea as a nitrogen source in a bioreactor.

09 BIOMASS FUELS↗
DOE OSTI2025

Populus PtrbHLH011 Is a Transcriptional Co‐Regulator Involved in the Activation of Cell Wall Biosynthesis by Iron Deprivation

The lack of a mechanistic understanding of the environmental plasticity of secondary cell wall (SCW) biosynthesis restricts large-scale biomass and bioenergy production on marginal lands. Using Populus (poplar), a key bioenergy crop, we discovered that iron deprivation, a prevalent abiotic stress on marginal lands, stimulates SCW biosynthesis in stems. We identified the transcription factor PtrbHLH011 as a critical regulator underlying this response. Through integrated analyses involving phenotypic characterisation of PtrbHLH011 knockout and overexpression plants, functional genomics and molecular investigations, we established that PtrbHLH011 functions as a central regulator of SCW biosynthesis, iron homeostasis and flavonoid biosynthesis by directly repressing essential genes in these pathways. Iron deprivation downregulates PtrbHLH011 expression, subsequently activating these biosynthetic pathways. Notably, cytosine base editing-based knockout of PtrbHLH011 significantly enhanced plant growth, yielding up to a 110% increase in stem diameter and a 300% increase in leaf iron content. These findings present a novel regulatory mechanism linking environmental iron availability to SCW biosynthesis and illustrate a practical strategy to improve biomass yield on iron-deficient marginal lands. Furthermore, our mechanistic insights into PtrbHLH011 target recognition and regulation provide a valuable foundation for precise manipulation of gene regulatory networks, facilitating the development of high-performance bioenergy crops adapted to marginal environments.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1976

Agricultural resources investigations in northern Italy and southern France (Agreste Project)

The author has identified the following significant results. The vegetation structure of rice was investigated and interpreted in dynamic terms as a significant factor governing the distribution of solar energy thoughout the canopy and therefore conditions the final yield. Radiometric characteristics of rice culture were described for various stages of development in relation to the vegetation structure in an attempt to establish correlations between data of total biomass and of grain yield. Qualitative classification results were encouraging although the discrimination achieved was far from complete.

Source record↗
DOE OSTI2024

Utilization of microalgae for agricultural runoff remediation and sustainable biofuel production through an integrated biorefinery approach

Generally wastewater such agricultural runoff is considered a nuisance; however, it could be harnessed as a potential source of nutrients like nitrates and phosphates in integrated biorefinery context. In the current study, microalgae Chlorella sp. S5 was used for bioremediation of agricultural runoff and the leftover algal biomass was used as a potential source for production of biofuels in an integrated biorefinery context. The microalgae Chlorella sp. S5 was cultivated on Blue Green (BG 11) medium and a comprehensive optimization of different parameters including phosphates, nitrates, and pH was carried out to acquire maximum algal biomass enriched with high lipids content. Dry biomass was quantified using the solvent extraction technique, while the identification of nitrates and phosphates in agricultural runoff was carried out using commercial kits. The algal extracted lipids (oils) were employed in enzymatic trans-esterification for biodiesel production using whole-cell biomass of Bacillus subtilis Q4 MZ841642. The resultant fatty acid methyl esters (FAMEs) were analyzed using Fourier transform infrared (FTIR) spectroscopy and gas chromatography coupled with mass spectrometry (GC–MS). Subsequently, both the intact algal biomass and its lipid-depleted algal biomass were used for biogas production within a batch anaerobic digestion setup. Interestingly, Chlorella sp. S5 demonstrated a substantial reduction of 95% in nitrate and 91% in phosphate from agricultural runoff. The biodiesel derived from algal biomass exhibited a noteworthy total FAME content of 98.2%, meeting the quality standards set by American Society for Testing and Materials (ASTM) and European union (EU) standards. Furthermore, the biomethane yields obtained from whole biomass and lipid-depleted biomass were 330.34 NmL/g VS added and 364.34 NmL/g VS added , respectively. In conclusion, the findings underscore the potent utility of Chlorella sp. S5 as a multi-faceted resource, proficiently employed in a sequential cascade for treating agricultural runoff, producing biodiesel, and generating biogas within the integrated biorefinery concept.

09 BIOMASS FUELS↗
NASA NTRS1989

Continuous hydroponic wheat production using a recirculating system

Continuous crop production, where plants of various ages are growing simultaneously in a single recirculating nutrient solution, is a possible alternative to batch production in a Controlled Ecological Life Support System. A study was conducted at John F. Kennedy Space Center where 8 trays (0.24 sq m per tray) of Triticum aestivum L. Yecora Rojo were grown simultaneously in a growth chamber at 23 C, 65 percent relative humidity, 1000 ppm CO2, continuous light, with a continuous flow, thin film nutrient delivery system. The same modified Hoagland nutrient solution was recirculated through the plant trays from an 80 L reservoir throughout the study. It was maintained by periodic addition of water and nutrients based on chemical analyses of the solution. The study was conducted for 216 days, during which 24 trays of wheat were consecutively planted (one every 9 days), 16 of which were grown to maturity and harvested. The remaining 8 trays were harvested on day 216. Grain yields averaged 520 g m(exp -2), and had an average edible biomass of 32 percent. Consecutive yields were unaffected by nutrient solution age. It was concluded that continual wheat production will work in this system over an extended period of time. Certain micronutrient deficiencies and toxicities posed problems and must be addressed in future continuous production systems.

Mackowiak, C. L.↗
DOE OSTI2023

Algal Biomass Conversion to Fuels via Combined Algae Processing (CAP): 2022 State of Technology and Future Research

The annual State of Technology (SOT) assessment is an essential activity for platform research conducted under the Bioenergy Technologies Office (BETO). It allows for the impact of research progress (both directly achieved in-house at NREL and furnished by partner organizations) to be quantified in terms of economic improvements in the overall biofuel production process for a particular biomass processing pathway, whether based on terrestrial or algal biomass feedstocks. As such, initial benchmarks can be established for currently demonstrated performance, and progress can be tracked toward out-year goals to ultimately demonstrate economically viable biofuel technologies. NREL's algae SOT benchmarking efforts focus both on front-end algal biomass production and separately on back-end conversion to fuels through NREL's "combined algae processing" (CAP) pathway. The production model is based on outdoor long-term cultivation data, enabled by comprehensive algal biomass production trials conducted under Development of Integrated Screening, Cultivar Optimization, and Verification Research (DISCOVR) consortium efforts and driven by data furnished by Arizona State University's (ASU's) Arizona Center for Algae Technology and Innovation (AzCATI) test bed site. The CAP model is primarily based on experimental efforts conducted under NREL research and development projects, with some process parameters provided by partner organizations. Assumptions regarding the wet storage of algae use data provided by Idaho National Laboratory (INL), while parts of the polyurethane production process leverage BETO-funded research from collaborators at Algenesis and the University of California, San Diego (UCSD). This report focuses on back-end conversion of algal biomass through the CAP pathway, highlighting the 2022 updates to minimum fuel selling price (MFSP). This update incorporates improvements to fermentation performance for two biological pathways through carboxylic acid and 2,3-butanediol (BDO) intermediates, as demonstrated through parallel research on the biochemical conversion of corn stover. Improvements are applied to the glucose fraction of the biomass only, while parameters regarding the conversion of the mannose fraction (not a significant component in corn stover) are maintained consistently with prior CAP SOTs. Additional parameters are also updated to reflect the most current understanding of each pathway, including an increase in the catalyst loading requirement in the ketonization step of the acids pathway and a decrease in the fermentation productivity in the BDO pathway. Additionally, the biomass feedstock costs (minimum biomass selling price [MBSP]), yields, and seasonal variability from the upstream cultivation SOT model were also incorporated into downstream Aspen Plus CAP models.

09 BIOMASS FUELS↗
DOE OSTI2024

Water use and radiation balance of miscanthus and corn on marginal land in the coastal plain region of North Carolina

Abstract Miscanthus is a perennial grass that can yield substantial amounts of biomass in land areas considered marginal. In the Coastal Plain region of North Carolina, marginal lands are typically located in coarse‐textured soils with low nutrient retention and water‐holding capacity, and high erosivity potential. Little is known about miscanthus water use under these conditions. We conducted a study to better understand the efficiency with which miscanthus uses natural resources such as water and radiant energy to produce harvestable dry biomass in comparison to corn, a typical commodity crop grown in the region. We hypothesized that under non‐limiting soil water conditions, miscanthus would have greater available energy and water use rates owing to its greater leaf area, thus leading to greater agronomic yields. Conversely, these effects would be negated under drought conditions. Our measurements showed that miscanthus intercepted more radiant energy than corn, which led to greater albedo (by 0.05), lower net radiation (by 4% or 0.4 MJ m −2 day −1 ), and lower soil heat flux (by 69% or 1.0 MJ m −2 day −1 ) than corn on average. Consequently, miscanthus had greater available energy (by 7% or 0.6 MJ m −2 day −1 ) and water use rates (by 14% or 0.5 mm day −1 ) than corn throughout the growing season on average, which partially confirmed our hypothesis. Greater water use rates and radiation interception by miscanthus did not translate to greater water‐use (1.5 g kg −1 vs. 1.6 g kg −1 ) and radiation‐use (0.9 g MJ −1 vs. 1.1 g MJ −1 ) efficiencies than corn. Compared to literature values, our data indicated that water and radiation availability were not limiting at our study site. Thus, it is likely that marginal land features present at the Coastal Plain region such as low soil fertility and high air temperatures throughout the growing season may constrain agronomic yields even if soil water and radiant energy are non‐limiting.

Carvalho, Henrique D. R.↗
DOE OSTI2021

Wheat respiratory O2 consumption falls with night warming alongside greater respiratory CO2 loss and reduced biomass

Abstract Warming nights are correlated with declining wheat growth and yield. As a key determinant of plant biomass, respiration consumes O2 as it produces ATP and releases CO2 and is typically reduced under warming to maintain metabolic efficiency. We compared the response of respiratory O2 and CO2 flux to multiple night and day warming treatments in wheat leaves and roots, using one commercial (Mace) and one breeding cultivar grown in controlled environments. We also examined the effect of night warming and a day heatwave on the capacity of the ATP-uncoupled alternative oxidase (AOX) pathway. Under warm nights, plant biomass fell, respiratory CO2 release measured at a common temperature was unchanged (indicating higher rates of CO2 release at prevailing growth temperature), respiratory O2 consumption at a common temperature declined, and AOX pathway capacity increased. The uncoupling of CO2 and O2 exchange and enhanced AOX pathway capacity suggest a reduction in plant energy demand under warm nights (lower O2 consumption), alongside higher rates of CO2 release under prevailing growth temperature (due to a lack of down-regulation of respiratory CO2 release). Less efficient ATP synthesis, teamed with sustained CO2 flux, could thus be driving observed biomass declines under warm nights.

Posch, Bradley C. (ORCID:0000000309246608)↗
DOE OSTI2024

The Effect of Air Separations on Fast Pyrolysis Products for Forest Residue Feedstocks

This study investigates the intricate relationship between biomass preprocessing and pyrolysis product yields, employing the air classification technique for the treatment of loblolly pine residues with varying moisture content. A comprehensive exploration of the physicochemical properties of air-classified loblolly pine informs a sophisticated pyrolysis simulation model. Given the complex and multifaceted nature of biomass pyrolysis, operating across diverse temporal and spatial scales, a pyrolysis kinetics-based CFD–DEM simulation method is employed to predict product yields. Results showed that the elevated moisture content amplifies particle adhesiveness, necessitating augmented air velocities for effective separation, thereby influencing the efficiency of the separation process. While carbon and hydrogen contents exhibit relative stability across diverse moisture contents and blower frequencies, the oxygen content undergoes noticeable changes. For example, the oxygen contents were measured as 29.2 and 38.6 wt% in the light fraction of 30% moisture content sample at blower frequencies of 10 and 20 Hz, respectively. An intriguing finding emerges from pyrolysis simulation, indicating that a lower blower frequency in air classification moderately enhances bio-oil yield and significantly improves its quality, particularly in terms of water content. For instance, the water content in the bio-oil was about 1.5% and 10% in the heavy and light fractions, respectively from 10% moisture sample under 15 Hz blower frequency. In summary, a detailed understanding and strategic manipulation of critical material attributes in biomass through efficient fractionation techniques are imperative for advancing fast pyrolysis as a sustainable avenue for renewable energy and chemical production.

09 BIOMASS FUELS↗
DOE OSTI2022

BETO 2021 Peer Review - 1.3.2.001 - Algae Biomass Composition

Addressing critical improvements in biomass productivity and associated biochemical composition is a priority for the economic and sustainable commercial development of biofuels and bioproducts from algae. Capitalizing on pathways that integrate engineering approaches with fundamental biochemistry of photosynthetic organisms will lead to a better understanding of the complex nexus of algae growth rates, productivity and composition. This project focuses on identifying the critical factors for economic development of fuel and bioproduct technologies. Algal compositional characteristics form the foundation of robust economic and business models. This project supports that foundation by developing and validating accurate compositional methods and disseminating them to the greater community. Simultaneously, we build a deep understanding of the dynamic biochemical composition and carbon allocation for biomass value and conversion yields. A co-product portfolio developed under this project demonstrated a 30% increase in intrinsic value. Additionally, an integrated pipeline of molecular diversity mapping for product discovery with quantitative demonstration across species was deployed over the BETO algae program. The advances made here are highly relevant to BETO's multi-year program targets of reducing costs and integrating dynamic biomass composition with conversion processes to provide options for bioproducts, all leveraging the molecular diversity of algae.

algal compositional characteristics↗
DOE OSTI2025

Lignin Removal in Subcellular Location of Poplar Cell Wall During Pretreatment Significantly Impacts Cellulose Digestibility

The γ-valerolactone (GVL) pretreatment is one of the leading solvent-based methods for producing high-quality lignin under mild conditions. However, the glucan conversion yield from GVL pretreated biomass remains unsatisfactory. To explore the discrepancies between the relatively low glucan conversion and high lignin extraction, we conducted GVL−HCl and NaOH pretreatments on poplar and investigated their effects on lignin content and location, as well as on enzymatic hydrolysis of poplar cell walls at the subcellular level. Under designated pretreatment conditions of GVL−HCl (90% GVL, 0.1 M HCl, 100 °C, 1 h) and NaOH (1 M, 121 °C, 2 h), the glucan conversion yields were 69.4% and 95.8%, with lignin removal rates of 67.8% and 47.7%, respectively. Four types of GFP-labeled carbohydrate binding modules were used to identify different forms of cellulose in the pretreated cell walls. The overall binding intensities to pretreated poplar were stronger for NaOH compared to GVL−HCl pretreatment. Stimulated Raman scattering microscopy imaging revealed that GVL−HCl preferentially extracted lignin from the compound middle lamella and cell corner areas, while NaOH effectively dissolved lignin in the secondary cell walls. Real-time imaging of cellulase degradation of pretreated cell walls further indicated that digestion started from both the cell lumen and the compound middle lamella areas for GVL, whereas it occurred uniformly across the secondary cell walls for NaOH. Our findings suggest that the location of lignin removal during pretreatment is crucial for enzymatic cellulose degradation, in addition to the total amount of lignin extraction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗