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The production of cellulosic sugars in lignocellulose biorefinery presents significant economic and environmental challenges due to the recalcitrant nature of biomass. The economic and facile production of renewable sugars with high yield and productivity is pivotal for the success of biorefinery. The cellulosic sugars are valorized either by biochemical routes or chemical routes or by hybrid (biological and chemical) routes into renewable chemicals, fuels, and materials. This manuscript focuses on the critical parameters affecting the economic viability of cellulosic sugar production at large scale, including biomass-specific pretreatment strategies and enzyme cost efficiency. High pretreatment costs, carbohydrate loss, and inhibitors production during pretreatment are identified as major contributors to overall production costs. To address these issues, we highlight the importance of developing cost-effective and efficient pretreatment methods tailored to specific biomass types and strategies for enzyme reuse and recycling. Future research should focus on innovations in pretreatment technologies, improved logistics for high-density feedstocks, biomass feeding systems, and advancements in enzyme technology to enhance the economic and environmental sustainability of lignocellulosic biorefineries. The findings highlight the need for continued innovation and optimization to make the commercial-scale production of cellulosic sugars more viable and sustainable. [ABSTRACT FROM AUTHOR]

A new forest biorefining model is emerging in which high‐value materials would be produced alongside a cellulosic sugar by‐product in facilities scaled to match fiber availability in northern forests. As these emerging biorefining technologies are being developed by private entities, the economics associated with them are little known. The goal of this study is to use publicly available information to carry out an initial techno‐economic assessment for two emerging biorefining technologies: one that produces sugar and hydrolysis lignin (H‐lignin) from thermomechanical pulping (TMP) and another that produces sugar, lignosulfonate, and nanocellulose. The break‐even price for H‐lignin and nanocellulose is estimated for the respective technology and a credit is applied for cellulosic sugar and other co‐product sales based on current market value. It was found that the minimum product selling price (MPSP) for H‐lignin was within the range of high purity lignin but not enough is known about the properties of H‐lignin to determine if this is a reasonable value for prospective end uses. The estimated MPSP of nanocellulose was found to be considerably lower than for more conventional nanocellulose‐producing methods that use Kraft or dissolving pulp as a starting point. The nanocellulose produced through the second process modeled has different properties than conventional nanocellulose, which need to be further explored. Having a sense of the cost to produce these novel materials will help to direct research on viable end uses. The methodology presented, using only publicly available information, can also be replicated for other emerging technologies. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Model of carbon transportation, delivery, and utilization for an algal biorefinery. • Potential of algae to utilize atmospheric or waste emissions of CO 2 is limited. • Pure sources of CO 2 represent the most promising option. • Hydrogen carbonate and cellulosic sugar are infeasible at scale. • Carbon is a limiting nutrient for the scalability of algal biofuels. Abstract Supplementation of carbon is critical for high productivity cultivation of most microalgae. Moreover, using microalgae for atmospheric CO 2 mitigation to combat climate change is promising as waste sources and atmospheric CO 2 can be utilized to produce useful products. The challenge is developing technologies, processes, and strategies that utilize carbon efficiently such that the overall system is sustainable. Through engineering system modeling combined with techno-economic and life-cycle assessments, this study examined the implications of various delivery methods of carbon to a production-scale algal biorefinery. Five primary carbon sources were considered: atmospheric CO 2 ; CO 2 from direct chemical or power plant waste emissions; CO 2 that has been concentrated from waste sources and compressed; inorganic carbon in the form of hydrogen carbonate; and organic carbon in the form of cellulosic sugars derived from corn stover. Each source was evaluated assuming co-location as well as pipeline transportation up to 100 km. Sustainability results indicate that economics are more prohibitive than energy and emissions. Of the scenarios evaluated, only two met both the economic and environmental criteria of contributing less than 0.50 US-$ GGE−1 and 20 g CO 2-eq MJ−1 to the overall system, respectively: uncompressed, pure sources of gaseous CO 2 with pipeline transportation of 40 km or less; and compressed, supercritical CO 2 from pure sources for pipeline transportation up to 100 km. A first order scalability assessment of algal biofuels based on these results shows carbon to be a limiting nutrient in an algal biorefinery with a total US production capability of 360 million gallons of fuel per year. [ABSTRACT FROM AUTHOR]

This study quantifies the cost of cellulosic sugar production using a fully-mechanical pretreatment process and fuel pellets as a co-product. The pretreatment reduces softwood forest harvest residuals to micron-sized amorphous particles. Energy consumption is minimized using a three-stage milling process. A techno-economic analysis was completed for a milling facility with saccharification and wood pellet manufacture. For the base case, concentrated sugar syrup can be produced for $0.496/kg of sugar. Sensitivity analyses were used to determine cost controlling variables, optimize the sugar cost and found that siting for this technology needs to strongly consider electricity cost and to a lesser extent local feedstock availability. If the sugar produced in this process is used to generate biofuel and is qualified for RIN credits through a life-cycle analysis, the effective cost could be reduced by $0.04–$0.06/kg of sugar. An additional $0.067/kg savings is possible if the biofuel facility is located adjacent or on-site; the finished sugar syrup would not have to be concentrated for transportation. An optimized scenario, including the RIN credit, dilute sugar syrup, and favorable energy costs and consumption, could reduce the cost to $0.34/kg sugar compared to $0.496/kg for the base case.

Abstract: In this paper, a novel risk analysis methodology is presented to evaluate the economic performance of a biorefinery given the volatility in the market price of the final product and the variability in the biomass delivered cost. In addition, potential economic incentives for participating biomass producers are quantified for different farm participation rates. The Monte Carlo simulation model, IBSAL‐MC, is used to estimate the biomass delivered cost distribution, and a modified risk heat map is used to visualize the expected return on investment (ROI) for various combinations of the market price of the final product and the biomass delivered cost. The developed methodology is applied to an under‐construction cellulosic sugar facility located in Sarnia, southwestern Ontario. Four farm participation rates of 20% (base‐case scenario), 30%, 40% and 50% are studied. The results show that the expected annual ROI for the base‐case scenario is estimated to be 1.3%. As the farm participation rate increases, the expected annual ROI increases from 1.3% at 20% farm participation rate to 3.4%, 4.6% and 5.1% at 30%, 40% and 50% rates, respectively. At high sugar market prices ($375–$525/tonne), the overall expected annual ROI increases to 9.5%, 11.4%, 12.6% and 13.0% in 20%, 30%, 40% and 50% farm participation rates, respectively. In this case, the economic incentives to share with biomass producers are estimated to be $14.10/dry tonne (dt), $15.77/dt and $16.33/dt by increasing the farm participation rate from 20% to 30%, 40% and 50%, respectively. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

In this paper, three scenarios are considered to quantify the impact of the biorefinery size on the required biomass logistical resources. The biorefinery scenarios include small scale (175 dt/day)-SS, medium scale (520 dt/day)-MS and large scale (860 dt/day)-LS. These scenarios are compared against the following logistical resources (1) harvest area and contracted fields, (2) logistics equipment fleet and the workforce to run this fleet and (3) intermediate storage sites and their biomass inventory levels. To this end, the IBSAL-MC simulation model is applied to a corn stover logistics system in Southwestern Ontario. The obtained results show (1) the harvest area and the number of contracted fields increase by 65% and 78% from the SS scenario to the MS and LS scenarios, respectively, (2) the average biomass delivered costs are estimated to be $82.09, $87.49 and $93.75/dry tonne in the SS, MS and LS scenarios. The increase in the capital costs to develop a dedicated logistics equipment fleet are estimated to be far greater than the increase in the delivered costs as the size of the biorefinery increases. The upfront capital costs are estimated to be $6.72, 21.83 and 35.51 million in these scenarios. To run the logistics equipment fleet efficiently, 37, 136 and 235 well-trained operators are required in the SS, MS ad LS scenarios, respectively, and (3) the inventory level and the land requirement for storage in the MS and LS scenarios are estimated to be 225% and 425% greater than those of the SS scenario. The sensitivity analysis indicates that the logistical resources are highly sensitive to corn yield and farm participation rate. Overall, this study shows the importance of considering the size of the required logistical resources and the associated level of logistical complexity in evaluating the economic viability of a biorefinery project. [ABSTRACT FROM AUTHOR]

Low-liquid aqueous ammonia (LLAA) pretreatment using aqueous ammonia was investigated to enhance enzymatic saccharification of corn stover. In this method, ground corn stover was simply contacted with aqueous ammonia mist (ammoniation step), followed by pretreatment at elevated temperature (90–150 °C) for an extended period (24–120 h) at different solid/liquid (S/L) ratios (0.29, 0.47 or 0.67), termed a pretreatment step. After that, excess (unreacted) ammonia was removed by evaporation, and the pretreated material was immediately saccharified by an enzyme without a washing step. The effects of key reaction parameters on both glucan digestibility and XMG digestibility were evaluated by analysis of variance (ANOVA). Under the best pretreatment conditions [S/L = 0.47, 0.16 (g NH3)/(g biomass), 90 °C, 24 h], LLAA pretreatment enhanced enzymatic digestibility from 23.1% for glucan and 11.3% for XMG (xylan + galactan + mannan) of untreated corn stover to 91.8% for glucan and 72.6% for XMG in pretreated solid.

N , N -dimethylformamide is frequently present in industrial wastewater and is environmentally detrimental. The current study aims to assess the utilization and biodegradation of N , N -dimethylformamide-containing wastewater to lessen the associated environmental load. Results show that addition of wastewater containing N , N -dimethylformamide to Trichoderma reesei fermentation media enhances cellulase production and facilitates cellulose hydrolysis. However, N , N -dimethylformamide is a cellulase enhancer that is not degraded during cellulase production in T. reesei fermentation and is retained in the N , N -dimethylformamide-enhanced cellulase solution. Indeed, the cellulosic sugar solution generated via lignocellulose hydrolysis with N , N -dimethylformamide-enhanced cellulase retains N , N -dimethylformamide. We further identified three core enzyme modules─ N , N -dimethylformamidase, dimethylamine dehydrogenase, and methylamine dehydrogenase enzyme─which were inserted into Escherichia coli to develop metabolically engineered strains. These strains degraded N , N -dimethylformamide and produced succinate using N , N -dimethylformamide-enhanced cellulosic sugar as the substrate. The platform described here can be applied to effectively convert waste into valuable bioproducts.

• Mixing CSS to molasses did not deteriorate ethanol production. • CSS + molasses mixed medium resulted in ∼27 % lower COD of spent wash. • Resulting spent wash suited biological treatment due to higher BOD/COD ratio. • CSS can be supplemental substrate to molasses-based ethanol production. Cellulosic sugar syrup (CSS), as a potential substrate to many biochemical industries, has been integrated into molasses-based ethanol production. It is seen as an additional substrate to alleviate the shortage of molasses supply. The impact of the CSS integration was assessed in terms of ethanol production and the quality of spent wash obtained after ethanol distillation. In this study, 0.02% (w/v) of urea was supplemented into molasses, as it is the minimum amount that provided high ethanol concentration and fermentation efficiency. Integrating CSS to molasses up to 28.5% (w/v) did not deteriorate the ethanol production nor fermentation efficiency. It also reduces the chemical oxygen demand (COD) of the spent wash by 24% when integrating at least 15% (w/v) of CSS to molasses, comparing to the value of the spent wash from molasses medium. The biodegradability of the spent wash also increased as compared to that of molasses medium. [ABSTRACT FROM AUTHOR]

[Display omitted] • Degradation extent of cellulose depends on the medium used in acid treatment. • Degradation extent of cellulose after acid-treated in alcohol is higher than in water. • Vapor pressure of methanol enhances acid degradation efficiency of cellulose. • Cellulose acid-treated in alcohols produces a higher ratio of sugars with DP 2−5. • Acid-treated in alcohols improves efficiency and controllability of cellulose degradation. Degradation of cotton and wood celluloses treated with hydrogen chloride in different media at 65 °C for 1−120 h was studied. Results showed the use of alcohol increased the cellulosic sugar content of hydrolysate as compared to water. Additionally, the recovery of celluloses treated in alcohols was lower than that of water, particularly when using 2-propanol and 1-butanol. After degradation, the crystallinity indices of celluloses changed slightly, and increased with treatment duration. The initial degradation rates of celluloses were in the order of 1-butanol > methanol > 2-propanol > ethanol > water. However, the decreases in weight-average degree of polymerization (DP w) plateaued after approximately 72 h for cotton cellulose and 5 h for wood cellulose, and the DP w after 120 h treatment were in the range of 98–195 and 196–364 AGU (anhydrous glucose unit), respectively. This study demonstrates the acid-degradation extent of cellulose can be tailored by the selection of degradation medium. Moreover, the alcohols tend to increase the penetration of acid and consequently facilitate the degradation, especially by using alcohols with higher carbon numbers. Additionally, the vapor pressure effect of methanol at 65 °C improved the degradation of cellulose. [ABSTRACT FROM AUTHOR]

Low-liquid aqueous ammonia (LLAA) pretreatment using aqueous ammonia was investigated to enhance enzymatic saccharification of corn stover. In this method, ground corn stover was simply contacted with aqueous ammonia mist (ammoniation step), followed by pretreatment at elevated temperature (90–150 °C) for an extended period (24–120 h) at different solid/liquid (S/L) ratios (0.29, 0.47 or 0.67), termed a pretreatment step. After that, excess (unreacted) ammonia was removed by evaporation, and the pretreated material was immediately saccharified by an enzyme without a washing step. The effects of key reaction parameters on both glucan digestibility and XMG digestibility were evaluated by analysis of variance (ANOVA). Under the best pretreatment conditions [S/L = 0.47, 0.16 (g NH3)/(g biomass), 90 °C, 24 h], LLAA pretreatment enhanced enzymatic digestibility from 23.1% for glucan and 11.3% for XMG (xylan + galactan + mannan) of untreated corn stover to 91.8% for glucan and 72.6% for XMG in pretreated solid. [ABSTRACT FROM AUTHOR]