Design of bioethanol green supply chain: Comparison between first and second generation biomass concerning economic, environmental and social criteria

Agricultural waste biomass for sustainable bioenergy production: Feedstock, characterization and pre-treatment methodologies

The worldwide trend in energy production is moving toward circular economy systems and sustainable availability of sources. Some advanced methods support the economic development of energy production by the utilization of waste biomass, while limiting ecological effects. The use of agro waste biomass is viewed as a major alternative energy source that expressively lowers greenhouse gas emissions. Agricultural residues produced as wastes after each step of agricultural production are used as sustainable biomass assets for bioenergy production. Nevertheless, agro waste biomass needs to go through a few cyclic changes, among which biomass pre-treatment contributes to the removal of lignin and has a significant role in the efficiency and yield of bioenergy production. As a result of rapid innovation in the utilization of agro waste for biomass-derived bioenergy, a comprehensive overview of the thrilling highlights and necessary advancements, in addition to a detailed analysis of feedstock, characterization, bioconversion, and contemporary pre-treatment procedures, appear to be vital. To this end, the current status in the generation of bioenergy from agro biomass through various pre-treatment procedures was examined in this study, along with presenting relevant challenges and a perspective for future investigations.

Coupling optimization with territorial LCA to support agricultural land-use planning

The life cycle assessment framework was adapted to the territorial level (the "territorial LCA") to assess the environmental impacts and services of land-use planning scenarios. Given the various geographical conditions of the territory, the potential alternatives of land-use scenarios could be enormous. To prevent the iterative process of proposing and comparing alternative scenarios, this work aims to move one step further to automatically generate optimal planning scenarios by linking the novel territorial LCA with multi-objective optimization (MOO). A fuzzy optimization approach is adopted to deal with the trade-offs among objectives and to generate optimized scenarios, minimizing the environmental damages and maximizing the satisfaction level of the desired land-use functions subjected to constraints such as area availability and demand. Geographical Information System (GIS) is employed to manipulate geographic datasets for spatial assessment. An illustrative case study tests the novel integrated method (the territorial LCA, MOO, and GIS) on its ability to propose optimal land-use planning for bioenergy production in a region in Belgium. The study results reveal the competition of land uses for different energy products, the trade-offs among impact categories, and potential impacts on other territories if implementing optimal land planning for the territory under study. The optimization outcomes can help decision-making on the optimal locations for different crop types (i.e., miscanthus, willow, and maize in the case study) and utilizations (i.e., electricity, heat, biogas, and bioethanol in this study) complying with the objectives and constraints. This integrated tool holds the potential to assist policymakers when deciding on how to use the territory facing the global context of increasing demands for multiple uses of bio-based products, such as for food, feed, fuel, fiber, and chemicals. Limitations of the current method and its potential for real-world applications are discussed, such as expanding the scope to include life cycle sustainability assessment and taking farmers' behavior and crop rotation into account.

The incorporated environmental policies and regulations into bioenergy supply chain management: A literature review

Bioenergy, a means to reach a sustainable economy, is being driven by governments by devising incremental regulations and more instrumental policies in parallel. These constant-changing regulations bring uncertainty to bioenergy supply chain optimization problems. An increasing number of recent studies on bioenergy supply chain optimization addressing environmental concerns have highlighted the need for an overview indispensable. The purpose of this paper is to present a review of the incorporated policies and regulations and to examine whether constraints or targets set by governments are fully met in optimizing of bioenergy supply chains. To this end, first, bioenergy policies and regulations enacted in the EU, the global leader in the energy transition, as a benchmark are reviewed based on the bioenergy supply chain steps. Then, the optimization problems employing policies and regulations are classified and discussed. The review reveals visible gaps between what policies demand and what is proposed in the literature, and underpin the regulations which need to be considered in future work. Examination of the literature also suggests that a globally drawn standard may lead to better bioenergy supply chain development considering other green energy developments. Our key finds are.

A Review of Trends in the Energy Use of Biomass: The Case of the Dominican Republic

This review examines the use of residual biomass as a renewable resource for energy generation in the Dominican Republic. The odology includes a thorough examination of scientific publications in recent years about logistics operations. The use of mathematical models can be beneficial for the selection of areas with a high number of residual biomass and processing centers; for the design of feedstock allocation; for the planning and selection of the mode of transport; and for the optimization of the supply chain, logistics, cost estimation, availability of resources, energy efficiency, economic performance, and environmental impact assessment. It is also essential to consider the exhaustive analysis of the most viable technological solutions among the conversion processes, in order to guarantee the minimum emissions of polluting or greenhouse gases. In addition, this document provides a critical review of the most relevant challenges that are currently facing logistics linked to the assessment of biomass in the Dominican Republic, with a straightforward approach to the complementarity and integration of non-manageable renewable energy sources.

Incorporating Environmental Perspective in Integrated Strategic-Tactical Economic Optimization Model of Biomass-to-Biofuel Supply Chain—A Real Case Study in Ethiopia

Several optimization models, which consider economic and environmental perspectives, have been developed recently to support the sustainable biomass-to-biofuel supply chain (BBSC) design. All of the economic-environmental optimization models rely on solving long-term planning problems with a conventional hierarchical approach, where tactical decisions are made based on the optimal strategic decisions from the strategic-level model, despite it arousing non-optimal solutions. Moreover, almost all of them have used non-monetary-based environmental indicators, which result in difficulties with clarity when comparing with economic objectives. Therefore, in this work, an effort is made to develop a more reliable planning strategy that offers optimal strategic and tactical decisions simultaneously and maximizes the economic and environmental benefits. Furthermore, the environmental performance of the BBSC has been assessed in terms of monetary value by adopting an ecocost approach after performing an LCA on the system. The integrated model is applied in the real biofuel sector of Ethiopia to optimize the country’s bioethanol and biodiesel supply chain over a 20-year horizon. Despite the abrupt rise in the model size, with it being a real countrywide case with many variables and large quantities of data, an alternative semi-heuristic method that offers a feasible solution to the multi-objective problem is provided.

Modeling and Optimization Sustainable Forest Supply Chain Considering Discount in Transportation System and Supplier Selection under Uncertainty

In recent decades, the forest industry has been growingly expanded due to economic conditions, climate changes, environmental and energy policies, and intense demand changes. Thus, appropriate planning is required to improve this industry. To achieve economic, social and environmental goals, a supply chain network is designed based on a multi-period and multi-product Mixed-Integer Non-Linear Programming (MINLP) model in which the objective is to maximize the profit, minimize detrimental environmental effects, improve social effects, and minimize the number of lost demands. In addition, to improve forest industry planning, strategic and tactical decisions have been implemented throughout the supply chain for all facilities, suppliers and machinery. These decisions significantly help to improve processes and product flows and to meet customers’ needs. In addition, because of the presence of uncertainty in some parameters, the proposed model was formulated and optimized under uncertainty using the hybrid robust possibilistic programming (HRPP-II) approach. The ε-constraint technique was used to solve the multi-objective model, and the Lagrangian relaxation (LR) method was utilized to solve the model of more complex dimensions. A case study in Northern Iran was conducted to assess the efficiency of the suggested approach. Finally, a sensitivity analysis was performed to determine the impact of important parameters on objective functions. The results of this study show that increasing the working hours of machines instead of increasing their number, increasing the capacity of some facilities instead of establishing new facilities and expanding the transport fleet has a significant impact on achieving predetermined goals.

Experimental investigation of the adsorption and desorption of cellulase enzymes on zeolite-β for enzyme recycling applications

The recyclability of cellulase enzymes using zeolite and polyethylene glycol (PEG) was investigated. The cellulase enzymes from cellulose hydrolysate suspensions were adsorbed onto zeolite-β under typical working conditions (pH 5). PEG having a molecular weight of 200 Da and 20 kDa was used as an eluent to desorb the cellulase enzymes from zeolite-β. Adsorption and desorption profiles of cellulase enzymes were studied by varying pH, PEG concentration, and salt concentration. Maximum binding capacity, q_m of the zeolite decreased by increasing the pH, or by introducing PEG. At pH 5, the q_m of the zeolite was determined to be 121 × 10^-3 g/g. About 24%, 51% and 75% of the adsorbed enzyme can be recovered using 1 M NaCl, PEG 200 and PEG 20000, respectively. The specific activity of the recovered enzyme increased by 57% due to the presence of residual PEG.

Operational Management Implemented in Biofuel Upstream Supply Chain and Downstream International Trading: Current Issues in Southeast Asia

Bioenergy is one of the alternatives to secure energy demand, despite increasing debate on the sustainability of using bioenergy as a renewable source. As the source is disseminated over a large area and affected by seasonality, the potential benefit is highly dependent on other cost and benefit trade-offs along the supply chain. This review paper aims to assess operational management research methods used in biofuel supply chain planning, including both upstream production and international downstream trading. There have been considerable operational management studies done on upstream processes in biofuel production based on different strategic and tactical decision making of a single or multiple feedstocks, considering economic and environmental factor. However, the environmental consideration is often limited to carbon emission where the other environmental impact such as land-use change, biodiversity loss, irrigation and fertilisation are often being overlooked. Biofuel supply chain and trading at international level remain as an apparent research potential where only limited numbers of global energy models explicitly simulate international bioenergy trade. The leading biofuel producing countries in Southeast Asia: Malaysia, Indonesia and Thailand, are selected as a case study to investigate further on how the supply chain management model could be applied considering the existing biofuel support policies. This study is expected to contribute to the selection of operational management research methods used for decision making under robust policy context, followed by several recommendations.

Bioethanol production by recycled Scheffersomyces stipitis in sequential batch fermentations with high cell density using xylose and glucose mixture

Here, it is shown three-step investigative procedures aiming to improve pentose-rich fermentations performance, involving a simple system for elevated mass production by Scheffersomyces stipitis (I), cellular recycle batch fermentations (CRBFs) at high cell density using two temperature strategies (fixed at 30°C; decreasing from 30 to 26°C) (II), and a short-term adaptation action seeking to acclimatize the microorganism in xylose rich-media (III). Cellular propagation provided 0.52gdrycellweightgRS(-1), resulting in an expressive value of 45.9gdrycellweightL(-1). The yeast robustness in CRBF was proven by effective ethanol production, reaching high xylose consumption (81%) and EtOH productivity (1.53gL(-1)h(-1)). Regarding the short-term adaptation, S. stipitis strengthened its robustness, as shown by a 6-fold increase in xylose reductase (XR) activity. The short fermentation time (20h for each batch) and the fermentation kinetics for ethanol production from xylose are quite promising.