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Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

This comprehensive review aims to elucidate the state of the art related to research trends regarding the use of brewer's spent grains (BSG), the main solid by‐product generated in breweries. Its status, future opportunities, and emerging trends were evaluated by bibliometric analysis, which contributed to clarifying the knowledge and perspectives in the field. In total, 510 documents were obtained from the Web of Science© database in a timespan from 1900 to 2020. VosViewer software and R‐bibliometrix package were used to investigate and map the most frequently cited papers, international collaborative networks, keywords, and the main countries and journals associated with this research. The results showed that, globally, 65 countries have been engaged in research related to BSG, and Brazil has been the most productive country, with up to 70 publications. Keyword analysis revealed that the studies on BSG are divided into four main knowledge areas: (i) pretreatment; (ii) nutritional quality; (iii) bioactive compounds, and (iv) pyrolysis. It was also found that a biorefinery can be designed for the complete utilization of BSG to obtain several valuable compounds. In this sense, different technological routes can be applied to produce arabinoxylans, proteins, ferulic acid, xylitol, xylose, lactic acid, butanol, biogas, fertilizer, and ethanol. In conclusion, BSG is a cost‐effective and feasible raw material for the sustainable production of bio‐based products and bioenergy and its valorization in a biorefinery is a powerful strategy to promote the circular economy transition of the beer industry. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Bioethanol production in Brazil gained momentum in the 1970s and 1980s as an energy security and energy sufficiency measure due to the well‐known world oil crisis. However, the increase in bioethanol production and consumption in the past couple of decades has been backed by the country's efforts and measures to reduce greenhouse gas (GHG) emissions in the transport sector. Brazil is the second largest producer of biofuels, and its production continues to increase because of the commitments made in the Paris Agreement in 2015. This study reviews several key policies designed to develop Brazilian bioethanol production and to protect the environment. It is argued that many of these policies do not consider land use change or encourage land protection to achieve sustainable land use and agricultural production. Thus, this work aims to understand the importance and impacts of public policies in expanding sugarcane in Brazil in the past 34 years, with regard to land use and native vegetation. The discussion in this paper addresses the inadequacy of current policies to avoid direct and indirect land use change caused by sugarcane expansion, despite incentives such as 17 Sustainable Development Goals from the United Nations and certification schemes. The data presented indicate an indirect effect caused by the expansion of sugarcane over pasture areas, which leads to further clearing of natural vegetation to establish new pasture areas. Ultimately, this study addresses the importance of zero deforestation in Brazil, regardless of the crop that causes the conversion. Without conjoint efforts by all sectors of the economy to curtail deforestation, the sustainability of producing biofuels is not guaranteed, as the emissions caused by deforestation will not be offset by the lower GHG emissions obtained by using ethanol as a transport fuel. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Background: Sucrose-rich sugarcane trash surpasses 28 million tons globally per year. Effective biorefinery systems could convert these biomasses to bioproducts, such as bioethanol from sugarcane sucrose in Brazil. Thermophilic microbes for biofuels have attracted great attention due to their higher fermentation temperature and wide substrate spectrum. However, few thermophiles using sucrose or molasses for biofuels production was reported. Thermoanaerobacterium aotearoense SCUT27 has been considered as an efficient ethanol producer, but it cannot directly utilize sucrose. In this study, various sucrose metabolic pathways were introduced and analyzed in Thermoanaerobaterium. Results: The sucrose-6-phosphate hydrolase (scrB), which was from a screened strain Thermoanaerobacterium thermosaccharolyticum G3-1 was overexpressed in T. aotearoense SCUT27 and endowed this strain with the ability to utilize sucrose. In addition, overexpression of the sucrose-specific PTS system (scrA) from Clostridium acetobutylicum accelerated the sucrose transport. To strengthen the alcohols production and substrates metabolism, the redox-sensing transcriptional repressor (rex) in T. aotearoense was further knocked out. Moreover, with the gene arginine repressor (argR) deleted, the ethanologenic mutant P8S10 showed great inhibitors-tolerance and finally accumulated ~ 34 g/L ethanol (a yield of 0.39 g/g sugars) from pretreated cane molasses in 5 L tank by fed-batch fermentation. When introducing butanol synthetic pathway, 3.22 g/L butanol was produced by P8SB4 with a yield of 0.44 g alcohols/g sugars at 50℃. This study demonstrated the potential application of T. aotearoense SCUT27 for ethanol and butanol production from low cost cane molasses. Conclusions: Our work provided strategies for sucrose utilization in thermophiles and improved biofuels production as well as stress tolerances of T. aotearoense SCUT27, demonstrating the potential application of the strain for cost-effective biofuels production from sucrose-based feedstocks. [ABSTRACT FROM AUTHOR]

The International Maritime Organization (IMO) has recently revised its strategy for shipping decarbonization, deepening the ambition to reduce annual greenhouse gas emissions by 2050. The accomplishment of this strategy requires the large-scale deployment of alternative maritime fuels, whose diversity and technical characteristics impose transition challenges. While several studies address the production of these fuels, a notable gap lies in the analysis of the required adaptations in vessels and ports for their usage. This study aims to fill this gap with a comprehensive review of material compatibility, storage in ports/vessels, and bunkering technology. First, we analyze key aspects of port/vessel adaptation: physical and chemical properties; energy conversion for propulsion; fuel feeding and storage; and bunkering procedures. Then, we perform a maturity assessment, placing each studied fuel on the technological readiness scale, revealing the most promising options regarding infrastructure adaptability. Finally, we develop a case study from Brazil, whose economy is grounded on maritime exports. The findings indicate that multi-product ports may have the potential to serve as multi-fuel hubs, while the remaining ports are inclined to specific fuels. In terms of vessel categories, we find that oil tankers, chemical ships, and gas carriers are most ready for conversion in the short term. [ABSTRACT FROM AUTHOR]

This review investigates the effects of the Brazilian agriculture production and forestry sector on carbon dioxide (CO2) emissions. Residual biomasses produced mainly in the agro-industrial and forestry sector as well as fast-growing plants were studied. Possibilities to minimize source-related emissions by sequestering part of carbon in soil and by producing biomass as a substitute for fossil fuel were extensively investigated. The lack of consistency among literature reports on residual biomass makes it difficult to compare CO2 emission reductions between studies and sectors. Data on chemical composition, heating value, proximate and ultimate analysis of the biomasses were collected. Then, the carbon sequestration potential of the biomasses as well as their usability in renewable energy practices were studied. Over 779.6 million tons of agricultural residues were generated in Brazil between 2021 and 2022. This implies a 12.1 million PJ energy potential, while 4.95 million tons of forestry residues was generated in 2019. An estimated carbon content of 276 Tg from these residues could lead to the production of approximately 1014.2 Tg of CO2. Brazilian biomasses, with a particular focus on agro-forest waste, can contribute to the development of sustainable alternative energy sources. Moreover, agro-waste can provide carbon credits for sustainable Brazilian agricultural development. [ABSTRACT FROM AUTHOR]

Biofuels are increasingly important renewable resources in the world's energy matrix that have challenged the scientific community as well as small and large farmers to develop alternatives to fossil fuels in order to achieve the aims of energy transition. In particular, Brazil's proven competitiveness in agribusiness together with its rich biodiversity put the country in a key position in the biofuels market. The semiarid Caatinga of northeastern Brazil, an exclusive biome rich in many oilseed species suitable for potential energy purposes, is of particular interest in this field. Nowadays, soybeans are the main feedstock used for the production of biodiesel, but, due to the increasing demand for biofuels, the search for alternative sources of oil from tropical flora with high productivity is crucial. Under this premise, this systematic review focuses on mapping Caatinga's vegetable oil crops that could be used as alternative raw materials for biofuels' production in Brazil, in addition to traditional soybeans and sugarcane. To gain more detailed insight into these matrices, their main properties, including oil content, fatty acid profile and physicochemical properties, are discussed. Moreover, an overview is provided of processes to synthesize different types of biofuels, particularly biodiesel and aviation biokerosene, including the routes employing homogeneous, enzymatic and mainly heterogeneous catalysts. Finally, future prospects and challenges for renewable biofuels and the Caatinga biome are addressed. [ABSTRACT FROM AUTHOR]

• We evaluate decarbonization of passenger transportation in Rio de Janeiro, Brazil. • Public transport and carpooled shared mobility rise system capacity and reduces CO 2. • Biofuels reduce CO 2 emissions at no increased system cost. • CO 2 price is the most effective decarbonization policy, but it is costlier. • Increased renewable electricity and electrification of the fleet reduce the most CO 2. This paper applies an energy systems model to evaluate how shared mobility (ride-hailing and shared autonomous vehicles), public buses, alternative energy sources (electricity and biofuels) and carbon pricing contribute to reduce passenger vehicles CO 2 emissions in Rio de Janeiro state, Brazil, from 2016 to 2050. Public buses and carpooled shared mobility increase system capacity, resulting in lower vehicle ownership, energy demand and CO 2 emissions, as well as savings per ton of CO 2 abated (from $3 to $4186). Biofuels reduce CO 2 emissions at no increased system cost, while carbon pricing is the most effective policy to reduce CO 2 emissions, but it is costlier than the alternatives and results in greater private vehicle use (up to 260%) if the expansion of zero-carbon public transportation remains limited due to technology adoption. The policy that reduces the most emissions (by 84%) combines the expansion of renewable electricity generation and implementation of a CO 2 price. [ABSTRACT FROM AUTHOR]

Second-generation technology (2G) is currently the industrial route that is being developed with the potential to meet the demand for biofuels and bioproducts. The technology studied in the present work is based on the non-food processing of sugarcane straw, which is unlike the bagasse processing route (a lignocellulosic residue) that is commonly used in boilers for steam and electricity generation. In the last years, cellulosic ethanol plants worldwide include the utilisation of corn stover, sugarcane bagasse, wood waste and plant residues. Therefore, a communication based on industrial aspects using sugarcane straw is important in order to expand the knowledge regarding this promising technology. The main objective of this work included listing the results obtained in a cellulosic-ethanol production industry using sugarcane straw, located in the Northeast region of Brazil and taking into account the efficiency of pre-treatment, enzymatic hydrolysis and fermentation processes and comparing these results with data found in the literature regarding studies with similar efficiency. It was possible to observe that the production of ethanol from sugarcane straw at an industrial scale achieved a productivity of 200 l of ethanol per tonne of biomass, exhibiting 90, 70 and 85% of pre-treatment, hydrolysis and fermentation efficiency, respectively. [ABSTRACT FROM AUTHOR]