Environmental analysis of bioethanol production strategies from corn stover via enzymatic and nonenzymatic sugar production

Biological-chemical conversion process design and machine learning-related life cycle assessment: Bio-lubricant production in a real case study of South Korea

This study explores the production of poly alpha olefin (PAO) from biomass as an environmentally friendly alternative to fossil fuel-based methods, aiming to reduce greenhouse gas (GHG) emissions. The primary goal is to design a process for converting 2,000 metric tons of biomass into PAO daily, integrating biological and chemical pathways. Environmental impact is assessed through a life cycle assessment (LCA), comparing this biomass-based method with traditional fossil fuel-derived processes. Key findings include the successful production of 458 metric tons of PAO, with the LCA revealing a 34.8% reduction in GHG emissions (9.88 kg CO2-eq./kg of PAO) compared to fossil fuel-based PAO. Sensitivity analyses on the oligomerization yield (60-70%, base case at 65%) and the recycle ratio of glucose in the bioprocess for octanoic acid production show significant environmental benefits when exceeding a 55% recycle ratio. Additionally, an energy scenario analysis predicts the impact of shifting to renewable energy by 2030. In a scenario where all electric utilities are renewable (RE100 scenario), GHG emissions are estimated at 13.07 kg CO2-eq./kg of PAO, further emphasizing the environmental advantage of biomass-based PAO. This study, through its integration of biological and chemical processes and comprehensive LCA, provides critical insights into the potential of biomass-based materials for reducing GHG emissions, making a substantial contribution to future research in high-value material production from renewable resources.

Co-immobilized multi-enzyme biocatalytic system on reversible and soluble carrier for saccharification of corn straw cellulose

Herein, three enzymes (cellulase, β-glucosidase, and pectinase) with synergistic effects were co-immobilized on the Eudragit L-100, and the recovery of co-immobilized enzymes from solid substrates were achieved through the reversible and soluble property of the carrier. The optimization of enzyme ratio overcomed the problem of inappropriate enzyme activity ratio caused by different immobilization efficiencies among enzymes during the preparation process of co-immobilized enzymes. The co-immobilized enzymes were utilized to catalytically hydrolyze cellulose from corn straw into glucose, achieving a cellulose conversion rate of 74.45% under conditions optimized for their enzymatic characteristics and hydrolytic reaction conditions. As a result of the reversibility and solubility of the carrier, the co-immobilized enzymes were recovered from the solid substrate after five cycles, retaining 54.67% of the enzyme activity. The aim of this study is to investigate the potential of co-immobilizing multiple enzymes onto the Eudragit L-100 carrier for the synergistic degradation of straw cellulose.

Organic waste derived bioethanol supply chain network: Multiobjective snapshot model with a real-Korea case study

Bioethanol, a promising biofuel gasoline additive, was recently produced by a new technology using acetic acid derived from organic waste. This study develops a multiobjective mathematical model with two competing minimization objectives: economy and environmental impact. The formulation is based on a mixed integer linear programming approach. The configuration of the organic-waste (OW)-based bioethanol supply chain network is optimized in terms of the number and locations of bioethanol refineries. The flows of acetic acid and bioethanol between the geographical nodes must meet the bioethanol regional demand. The model is validated in three real-scenario case studies with different OW utilization rates (30%, 50%, and 70%) in South Korea in the near future (2030). The multiobjective problem is solved using the ε-constraint method and the selected Pareto solutions balance the trade-off between the economic and environmental objectives. At the "best-choice" solution points, increasing the OW utilization rate from 30% to 70% decreased the total annual cost from 904.2 to 707.3 million $/yr and the total greenhouse emissions from 1087.2 to -15.7 CO₂ equiv./yr.

Techno-economic analysis and life cycle assessment of poly (butylene succinate) production using food waste

In this present study, the production of poly (butylene succinate) (PBS) from food waste was investigated and critical factors were evaluated. The economic feasibility of the process was investigated, as well as the minimum selling price (MSP) of PBS and sensitivity analysis of economic factors based on critical input parameters. 1,4-butanediol price and solvent usage in PBS purification significantly impacted economics during the process. In this process, the MSP of PBS was 3.5 $/kg. The Monte Carlo simulation technique was used to determine the uncertainty in the MSP of PBS. The plant's return on investment (ROI), payback period, internal rate of return (IRR), and net present value (NPV) were 15.79 %, 6.33 years, 16.48 %, and 58,879,000 USD, respectively. The environmental impact factors were evaluated. The results showed the GHG emission from the process was 5.19 kg CO₂-eq/kg of PBS which is low than conventional PBS production.

Lifecycle assessment of methanol production from blast furnace gas

A technological scenario configuration for producing methanol (MeOH) from blast furnace gas (BFG) with natural gas (NG)-based energy generation was evaluated by a rigorous life cycle assessment. The new BFG scenario was compared to a conventional BFG scenario-BFG energy generation with NG-based MeOH production. In all, 18 environmental impact categories were estimated for both technological BFG scenario configurations on a conceptual plant level. The results of a case study in South Korea indicated that the new BFG scenario performs better for 12 environmental impacts (20-97% lower), but fossil resource depletion is worse because NG is used for the displacement of energy generation. The robustness of the environmental impact results for the new BFG scenario was supported by a case study, which highlighted that the primary source for the displacement of energy generation is crucial.

Recent advances in valorization of organic municipal waste into energy using biorefinery approach, environment and economic analysis

Researcher's all around works on a copious technique to lessen waste production and superintend the waste management for long-term socio-economic and environmental benefits. Value-added products can be produced from municipal waste by using holistic and integrated approaches. In this review, a detail about the superiority of the different methods like anaerobic digestion, biofuel production, incineration, pyrolysis and gasification were used for the conversion of municipal waste to feedstock for alternate energy and its economic- environmental impacts were consolidated. Most conversion techniques were environmentally friendly to manage municipal waste. The biological process was more economically feasible compare to the thermal process, for the reason thermal process required a large amount of capital investment and energy utilization. In the thermal process, gasification shows low emission, and pyrolysis shows low capital investment and economically feasible compare to other thermal processes. Waste to energy technology significantly reduced the emission and energy demand.