Brazilian Biorefinery Research Articles

Life Cycle Analysis of Succinic Acid Production in the Brazilian Biorefinery Context

Succinic acid is an essential component of the chemical industry. Traditionally produced from fossil resources, its sustainable production using renewable resources faces challenges due to the complexities of cultivation and purification. This study assessed the environmental impacts of succinic acid production from sugarcane through a life cycle analysis and compared it with three other scenarios: using sorghum, apple pomace, and the traditional chemical route. Employing the ReCiPe midpoint methodology with a cradle-to-gate approach, the analysis highlighted significant environmental impacts linked to the agricultural stage in the sugarcane process. The use of pesticides, fertilizers, and energy demand resulted in elevated impacts compared to other stages of the process. The other scenarios also presented strong contributions in the purification stages. The production from sugarcane proved advantageous compared to other scenarios, minimizing impacts in 6 out of 10 categories. It is evident that the selection of the correct biomass is crucial for process sustainability, and the use of second-generation inputs can help reduce impacts in the agricultural stage. However, advancements in the fermentation stage are necessary, along with a reduction in the complexity of the purification steps. This study emphasizes the potential of renewable succinic acid production from sugarcane juice in the Brazilian scenario. Utilizing this process could reduce succinic acid’s environmental impacts by 70% to 99% compared to the petrochemical route. The process should be considered as a sustainable alternative to be included in the portfolio of biorefineries, enhancing factory profitability.

Ethanol yield calculations in biorefineries.

The ethanol yield on sugar during alcoholic fermentation allows for diverse interpretation in academia and industry. There are several different ways to calculate this parameter, which is the most important one in this industrial bioprocess and the one that should be maximized, as reported by Pereira, Rodrigues, Sonego, Cruz and Badino (A new methodology to calculate the ethanol fermentation efficiency at bench and industrial scales. Ind Eng Chem Res 2018; 57: 16182-91). On the one hand, the various methods currently employed in industry provide dissimilar results, and recent evidence shows that yield has been consistently overestimated in Brazilian sugarcane biorefineries. On the other hand, in academia, researchers often lack information on all the intricate aspects involved in calculating the ethanol yield in industry. Here, we comment on these two aspects, using fuel ethanol production from sugarcane in Brazilian biorefineries as an example, and taking the work of Pereira, Rodrigues, Sonego, Cruz and Badino (A new methodology to calculate the ethanol fermentation efficiency at bench and industrial scales. Ind Eng Chem Res 2018; 57: 16182-91.) as a starting point. Our work is an attempt to demystify some common beliefs and to foster closer interaction between academic and industrial professionals from the fermentation sector. Pereira, Rodrigues, Sonego, Cruz and Badino (A new methodology to calculate the ethanol fermentation efficiency at bench and industrial scales. Ind Eng Chem Res 2018; 57: 16182-91).

Brazilian biorefineries from second generation biomass: critical insights from industry and future perspectives

AbstractTransitioning from gasoline and petroleum‐based products to biofuels and green chemicals is a paradigm shift that will lead to the development of the bioeconomy. In this sense, the role of biorefineries in countries like Brazil is very important as the country generates a huge amount of second generation (2G) biomass every year and also has an attractive consumable market. However, technological innovations are still required to unleash the fullest potential of biomass conversion to biofuels and biochemicals, although successful examples are already a reality. For example, Amyris Inc. has developed renewable products for cosmetics (squalene), healthcare (artemisinin), and flavors / fragrances, and Suzano Papel e Celulose has developed sustainable technologies for the production of pulp and paper, and lignin‐derived adhesives (Ecolig). First‐generation ethanol in Brazil is an established source of transportation fuel but 2G ethanol production with low production costs is still a challenge at commercial scale, and companies like Raízen and GranBio continue making efforts to improve the economic feasibility of the adopted processes. In this context, the RenovaBio Policy launched by the Federal Brazilian Government in December 2017 aims to boost the production and utilization of biofuels and green chemicals in the country. Considering the matters mentioned above, this paper discusses the Brazilian biorefinery developments, technological advances, and current industrial scenario for the production of biofuels and chemicals. © 2021 Society of Industrial Chemistry and John Wiley & Sons Ltd.

Towards high-temperature fuel ethanol production using Kluyveromyces marxianus: On the search for plug-in strains for the Brazilian sugarcane-based biorefinery

In the production of fuel ethanol from sugarcane in Brazilian biorefineries, one way to achieve lower production costs is the fermentation of sugars into ethanol at high temperatures (˜48 °C), which could lead to a decrease in: contamination levels, use of antibiotics, cooling costs, water usage, use of sulphuric acid in cell recycling, and energy used in distillation. Since Saccharomyces cerevisiae, the yeast species used in these biorefineries, cannot grow at these temperatures, alternative organisms need to be employed and one candidate is Kluyveromyces marxianus. Here, 20 strains belonging to this species were screened for their capacity to thrive at high temperatures (37, 45 and 48 °C) and under conditions relevant in the fuel ethanol industry: low pH (2.5), anaerobiosis, and high ethanol concentrations (up to 10%). The ethanol producing capacity of some strains was also evaluated and the ethanol yield on sugar quantified. Strains K. marxianus NCYC 3396 and UFV-3 stood out as potential microorganisms to be plugged into this industry (metabolic, evolutionary and reverse engineering will be required), since they grew better than the remaining ones under most of the conditions tested and produced ethanol at 48 °C with similar yields (0.40 g ethanol.g glucose−1) to those displayed by S. cerevisiae at 37 °C.

Seasonal characterization of sugarcane vinasse: Assessing environmental impacts from fertirrigation and the bioenergy recovery potential through biodigestion

Sugarcane vinasse has been widely used as a soil fertilizer in the Brazilian sucro-alcohol industry for recycling potassium and water. However, the potential negative effects from long-term soil fertirrigation represent a major drawback regarding this practice, whereas the application of biodigestion represents an efficient method for reducing the polluting organic load and recovering bioenergy from vinasse. Regardless of the predicted use for vinasse, an understanding of the potential of each option is imperative, as the seasonal alterations in the inorganic/organic fractions of vinasse directly affect its management. In this context, this study presents a detailed compositional characterization of sugarcane vinasse from a large-scale Brazilian biorefinery throughout the 2014/2015 harvest to assess the environmental effects (due to fertirrigation) and to estimate the biogas energetic potential. Calculated inputs of organic matter into soils due to vinasse land application were equivalent to the polluting load of populations (117–257inhabha−1) at least 2-fold greater than the largest Brazilian capital cities (78–70inhabha−1). Two-phase biodigestion could efficiently reduce the polluting load of vinasse (23–52inhabha−1) and eliminate the negative effects from direct sulfide emissions in the environment. However, a high risk of soil sodification could result from using high doses of Na-based alkalizing compounds in biodigestion plants. Finally, the optimized recovery of bioenergy through biogas (13.3–26.7MW as electricity) could supply populations as large as 305 thousand inhabitants, so that over 30% of the surplus electricity produced by the studied biorefinery could be obtained from biogas. Overall, applying biodigestion in the treatment of vinasse provides important environmental and energetic gains. However, the benefits of reducing the polluting organic load of vinasse through bioenergy recovery may lose their effect depending on the alkalizing strategy, indicating that the proper use of chemicals in full-scale biodigestion plants is imperative to attain process sustainability.

Development of a low-cost cellulase production process using Trichoderma reesei for Brazilian biorefineries

BackgroundDuring the past few years, the first industrial-scale cellulosic ethanol plants have been inaugurated. Although the performance of the commercial cellulase enzymes used in this process has greatly improved over the past decade, cellulases still represent a very significant operational cost. Depending on the region, transport of cellulases from a central production facility to a biorefinery may significantly add to enzyme cost. The aim of the present study was to develop a simple, cost-efficient cellulase production process that could be employed locally at a Brazilian sugarcane biorefinery.ResultsOur work focused on two main topics: growth medium formulation and strain improvement. We evaluated several Brazilian low-cost industrial residues for their potential in cellulase production. Among the solid residues evaluated, soybean hulls were found to display clearly the most desirable characteristics. We engineered a Trichoderma reesei strain to secrete cellulase in the presence of repressing sugars, enabling the use of sugarcane molasses as an additional carbon source. In addition, we added a heterologous β-glucosidase to improve the performance of the produced enzymes in hydrolysis. Finally, the addition of an invertase gene from Aspegillus niger into our strain allowed it to consume sucrose from sugarcane molasses directly. Preliminary cost analysis showed that the overall process can provide for very low-cost enzyme with good hydrolysis performance on industrially pre-treated sugarcane straw.ConclusionsIn this study, we showed that with relatively few genetic modifications and the right growth medium it is possible to produce considerable amounts of well-performing cellulase at very low cost in Brazil using T. reesei. With further enhancements and optimization, such a system could provide a viable alternative to delivered commercial cellulases.

Hybrid Input‐Output Life Cycle Assessment of First‐ and Second‐Generation Ethanol Production Technologies in Brazil

SummaryA hybrid approach combining life cycle assessment and input‐output analysis was used to demonstrate the economic and environmental benefits of current and future improvements in agricultural and industrial technologies for ethanol production in Brazilian biorefineries. In this article, three main scenarios were evaluated: first‐generation ethanol production with the average current technology; the improved current technology; and the integration of improved first‐ and second‐generation ethanol production. For the improved first‐generation scenario, a US$1 million increase in ethanol demand can give rise to US$2.5 million of total economic activity in the Brazilian economy when direct and indirect purchases of inputs are considered. This value is slightly higher than the economic activity (US$1.8 million) for an energy equivalent amount of gasoline. The integration of first‐ and second‐generation technologies significantly reduces the total greenhouse gas emissions of ethanol production: 14.6 versus 86.4 grams of carbon dioxide equivalent per megajoule (g CO2‐eq/MJ) for gasoline. Moreover, emissions of ethanol can be negative (–10.5 g CO2‐eq/MJ) when the system boundary is expanded to account for surplus bioelectricity by displacement of natural gas thermal electricity generation considering electricity produced in first‐generation optimized biorefineries.

High organic loading rate on thermophilic hydrogen production and metagenomic study at an anaerobic packed-bed reactor treating a residual liquid stream of a Brazilian biorefinery

This study evaluated the influence of a high organic loading rate (OLR) on thermophilic hydrogen production at an up-flow anaerobic packed-bed reactor (APBR) treating a residual liquid stream of a Brazilian biorefinery. The APBR, filled with low-density polyethylene, was operated at an OLR of 84.2kg-CODm−3d−1. This value was determined in a previous study. The maximum values of hydrogen production and yield were 5,252.6mL-H2d−1 and 3.7mol-H2mol−1total carbohydrates, respectively. However, whereas the OLR remained constant, the specific organic load rate (sOLR) decreased throughout operation from 1.38 to 0.72g-Total carbohydratesg-VS−1h−1, this decrease negatively affected hydrogen production. A sOLR of 0.98g-Total carbohydratesg-VS−1h−1 was optimal for hydrogen production. The microbial community was studied using 454-pyrosequencing analysis. Organisms belonging to the genera Caloramator, Clostridium, Megasphaera, Oxobacter, Thermoanaerobacterium, and Thermohydrogenium were detected in samples taken from the reactor at operation days 30 and 60, suggesting that these organisms contribute to hydrogen production.