Sugarcane, a perennial grass native to the warm temperate to tropical regions of South Asia and Melanesia, has become one of the globe's most prolific crops, deeply entrenched in the agricultural economies of many countries. As a cornerstone of the agricultural sector, sugarcane not only provides the raw material for a significant portion of the world's sugar production but also serves as a vital source for biofuels, particularly ethanol, contributing to the energy matrix of nations such as Brazil. The global importance of sugarcane is underscored by its role in supporting livelihoods, contributing to food security, and its emerging use in a variety of bio-based products (Solomon et al., 2019).

However, the intensification of sugarcane cultivation and processing has raised substantial concerns regarding sustainability. The environmental footprint of sugarcane processing is considerable, generating vast amounts of solid and liquid waste that, if not managed properly, can lead to detrimental effects on ecosystems and human health (Ungureanu et al., 2022). The sustainability of sugarcane cultivation itself is also under scrutiny, with issues such as soil erosion, water depletion, and the use of agrochemicals posing significant challenges. Moreover, the social implications of sugarcane production, including labor conditions and the potential displacement of food crops by energy crops, add complexity to the sustainability discourse.

Recognizing these challenges, there is a growing need to adopt sustainable practices in sugarcane processing that harmonize environmental stewardship with economic viability. The valorization of waste and by-products through innovative technologies offers a pathway to a more circular bioeconomy, where waste is transformed into valuable resources, thereby reducing environmental impacts and enhancing economic outcomes. Furthermore, decision support systems and sustainability assessments are being developed to guide the sugarcane industry towards more sustainable production systems (Chico et al., 2022).

This study aims to outline the environmental and economic challenges associated with sugarcane processing and to review the technologies and practices that can mitigate these challenges The scope of analysis will encompass the environmental impacts of waste generation, the economic implications of by-product valorization, and the social dimensions of sugarcane production. By synthesizing the findings from recent research, this paper seeks to provide a comprehensive overview of the sustainability of sugarcane processing and to offer insights into the pathways for achieving a more sustainable sugarcane industry.

1 Overview of Sugarcane Processing

1.1 Current processing methods

Sugarcane processing involves several steps, starting with the cultivation of the sugarcane crop, followed by harvesting, milling, and processing of by-products. The juice extracted from sugarcane stalks is the primary raw material for sugar production, which accounts for 86% of global sugar output (Ungureanu et al., 2022). During milling, the stalks are crushed to extract the juice, and the remaining fibrous material, known as bagasse, is often used as a biofuel for energy production. The processing also generates significant quantities of solid and liquid waste, including straws, press mud, wastewater, ash from bagasse incineration, vinasse from ethanol distillation, and molasses. Recent developments in sugarcane processing have focused on incremental improvements aimed at reducing costs and enhancing revenue, with particular attention to exploiting the energy value of sugarcane (Rein, 2019).

1.2 Environmental impact

The environmental challenges associated with sugarcane processing are substantial. Annually, more than 279 million tons of waste are generated, posing risks to environmental factors and human health if not properly managed. The burning of sugarcane for harvesting contributes to atmospheric pollution. Additionally, sugarcane cultivation impacts include global warming, human toxicity, terrestrial acidification, freshwater and marine eutrophication, and ecotoxicity (Ungureanu et al., 2022). Water depletion and the degradation of soils and aquatic systems are also significant concerns. However, the valorization of waste and by-products has gained momentum, contributing to sustainable development and circular bioeconomy.

1.3 Economic impact

Economic factors in sugarcane processing include the cost of production, profitability, and market challenges. The competitiveness of sugarcane for food and fuel production is influenced by environmental and economic factors, such as the demand for bioethanol and the emergence of electric vehicles (Silalertruksa and Gheewala, 2020). Mechanized harvesting can reduce production costs but may increase environmental impacts and reduce employment. The sugarcane industry is also affected by fluctuating sugar prices and the need to diversify for sustainability. The concept of sugarcane biorefineries, which integrate the production of sugar, ethanol, and other bio-based products, has been proposed to improve economic and environmental sustainability.

In conclusion, while sugarcane processing is a significant economic activity, it faces environmental and economic challenges that must be addressed to ensure its sustainability. The integration of environmental and economic perspectives is crucial for the development of sustainable sugarcane processing practices.

2 Environmental Perspectives on Sustainability

2.1 Sustainable agricultural practices

Sustainable agricultural practices are essential for minimizing the environmental impact of sugarcane cultivation. Crop rotation, organic farming, and reduced chemical use are among the techniques that can enhance sustainability. In North-eastern Thailand, the environmental and socio-economic impacts of sugarcane cultivation were assessed, revealing that freshwater ecotoxicity, eutrophication, and marine ecotoxicity were the most significant impacts (Kumar et al., 2020). Sustainable practices such as optimal fertilizer and pesticide application can increase yields, thereby reducing environmental impacts and production costs. Additionally, mechanized harvesting, while reducing labor costs, can lead to increased environmental impacts and reduced employment, suggesting a need for balanced approaches.

2.2 Innovations in processing technology

Advancements in processing technology are crucial for reducing the environmental footprint of sugarcane processing. The valorization of waste and by-products from sugarcane processing contributes to sustainable development and a circular bioeconomy. Technologies for waste valorization range from well-established to innovative ones still in development (Rabelo et al., 2020). These technologies aim to transform waste into biofuels and other value-added products, thereby enhancing environmental sustainability and contributing to human health. Mechanized farming combined with cane trash utilization for power generation has been identified as a highly eco-efficient system, improving the value added of the biorefinery while decreasing greenhouse gas emissions.

2.3 Impact assessment

Evaluating the effectiveness of sustainable practices and technologies is critical for reducing the environmental footprint of sugarcane production. Life cycle assessment (LCA) approaches have been used to model the primary energy inputs and greenhouse gas emissions associated with sugarcane production in South Africa, demonstrating that green cane harvesting can reduce energy inputs and emissions significantly. In Brazil, non-burning sugarcane harvesting has been identified as a win-win strategy, benefiting both agronomic and environmental aspects, although issues such as soil compaction remain. Furthermore, the eco-efficiency indicator has been used to assess the combined environmental and economic sustainability of sugarcane biorefineries (Sydney et al., 2021), with scenarios involving mechanized farming and cane trash utilization showing the highest eco-efficiency. These assessments highlight the potential for sustainable sugarcane production to contribute to environmental protection while maintaining economic viability.

3 Economic Perspectives on Sustainability

3.1 Cost-effectiveness of sustainable practices

The economic viability of implementing sustainable practices in sugarcane processing is multifaceted. Sustainable practices, such as the adoption of best management practices including conservation tillage and sustainable crop residue management, can enhance soil health and carbon sequestration, which are vital for long-term productivity (Cherubin et al., 2021). The transition from low-productivity pastures to sugarcane cultivation, particularly in Brazil, has been identified as a sustainable pathway that not only increases bioenergy production but also improves soil health over time. Moreover, the valorization of waste and by-products from sugarcane processing contributes to the sustainability of the environment, agriculture, and human health, while also providing economic benefits by transforming waste into valuable resources. The adoption of green technologies in sugarcane production, such as nutrient management strategies and crop residue recycling, can reduce the cost of production and improve soil health, thereby enhancing cane yield and sugar recovery (Shukla et al., 2019).

3.2 Economic benefits

In the long term, sustainable sugarcane processing practices can lead to improved efficiency and better product quality. The utilization of sugarcane industrial by-products in agriculture can replace chemical fertilization, which is cost-effective and eco-friendly, leading to value-added soil properties and increased crop yield (Raza et al., 2021). Additionally, sustainable nutrient management in sugarcane fields can maintain productivity in the long term, ensuring profitability (Kusumawati and Alam, 2021). Mechanized sugarcane production systems, which include the recovery of straw, have been associated with lower ethanol production costs and higher internal rates of return due to increased ethanol yield and electricity surplus, indicating significant economic benefits.

3.3 Policy and incentives

Governmental policies and economic incentives play a crucial role in promoting sustainability in sugarcane processing. Public policies and well-designed legal frameworks, such as the Forest Code and the RenovaBio legislations in Brazil, are necessary to make bioenergy production compatible with rational land use and protection (Cherubin et al., 2021). The economic viability of sugarcane cultivation is also influenced by the benefits provided to growers, such as secure markets and subsidized inputs, which are often supported by government policies (Abnave, 2021). However, the economic viability analysis indicates that while sugarcane cultivation is profitable, it involves risks related to farm profitability and sustainable use of farm resources, highlighting the need for technical solutions to reduce operation costs.

In conclusion, the integration of environmental and economic perspectives in sugarcane processing reveals that sustainable practices not only contribute to environmental conservation but also offer economic advantages that can be further enhanced by supportive policies and incentives.

4 Case Studies and Practical Examples

4.1 Successful implementations

Sustainable practices in the sugarcane industry have been successfully implemented in various regions, demonstrating the potential for environmental and socio-economic improvements. In north-eastern Thailand, a case study revealed that optimizing fertilizer and pesticide use, along with mechanized harvesting, could increase yields, lower environmental impacts, and reduce production costs, although mechanization is associated with increased environmental impacts and reduced employment. Similarly, the integration of biomass gasification and Fischer–Tropsch synthesis in sugarcane biorefineries has shown a significant reduction in greenhouse gas emissions, by 85%~95% compared to fossil equivalents, and the potential for higher economic performance when energy-cane is processed (Bressanin et al., 2020).

The valorization of waste and by-products from sugarcane processing has also been a focus, with technologies established for converting waste into biofuels and other value-added products, contributing to the sustainability of the environment, agriculture, and human health (Ungureanu et al., 2022). In Thailand, the implementation of a sugarcane biorefinery system that utilizes cane trash for power generation was found to yield the highest eco-efficiency, improving economic value and reducing greenhouse gas emissions.

4.2 Comparative analysis

Comparing traditional and sustainable practices in the sugarcane industry reveals significant differences in environmental and economic outcomes. In Tucumán, Argentina, life cycle assessments showed that high technology levels in agriculture, which avoid pre-harvest burning and use better cultural practices, result in lower environmental impacts across several categories. In Thailand, a life cycle assessment of sugarcane biorefinery systems indicated that green cane production and integrated biomass residue utilization could substantially reduce environmental impacts, with potential reductions in climate change impacts by 38% and fossil depletion by 21% (Khumla et al., 2022).

Conversely, a sustainability assessment of large-scale ethanol production from sugarcane highlighted the environmental and natural resource impacts of such systems, with low renewability and significant consumption of topsoil, water, and land. A techno-economic analysis in Colombia suggested that a biorefinery producing fuel ethanol and PHB from combined cane bagasse and molasses could offer the best economic, environmental, and social performance.

The inclusion of anaerobic digestion of vinasse in sugarcane biorefineries has been analyzed, showing positive impacts on productivity and sustainability, with an increase in surplus electric energy and reduced environmental impacts in almost all categories (Longati et al., 2020). Lastly, an environmental and social life cycle assessment in Thailand identified cane trash burning and overuse of chemical fertilizers as key issues, suggesting that addressing these could enhance the sustainability of sugarcane-based products.

5 Challenges and Opportunities

5.1 Barriers to implementation

The adoption of sustainable practices in sugarcane processing faces several challenges that can hinder progress across the industry. One of the primary barriers is technological limitations. While advanced technologies exist that can reduce environmental impacts and enhance efficiency, they often require significant upfront investments and are not always readily accessible to small-scale producers or in developing regions. For example, high-efficiency irrigation systems and mechanized harvesting equipment are capital-intensive and may not be economically feasible for smaller operations.

Financial constraints are another significant barrier. The initial cost of transitioning to sustainable technologies and practices can be prohibitive. This is compounded by the lack of adequate financial support mechanisms, such as loans, subsidies, or incentives, which are crucial for encouraging investment in sustainable technologies. Additionally, the return on investment for such technologies may not be immediately apparent, discouraging stakeholders from committing the necessary funds.

Regulatory challenges also play a critical role. Inconsistent and fragmented regulatory frameworks can create uncertainty among producers, making it difficult to implement uniform sustainable practices. Furthermore, in some regions, there is a lack of stringent regulations to enforce sustainable practices, which allows less sustainable but more cost-effective methods to dominate.

5.2 Opportunities for innovation

Despite these challenges, there are significant opportunities for innovation and further research in sustainable sugarcane processing that can pave the way for more widespread adoption of environmentally friendly practices. One major area for innovation is the development of low-cost, scalable technologies that are accessible to all producers, regardless of their size. For example, research into more efficient use of agrochemicals through precision agriculture could minimize environmental impacts while also reducing costs.

Improving waste valorization presents another opportunity. Sugarcane processing generates large amounts of waste, such as bagasse and vinasse. Developing technologies that can efficiently convert these by-products into bioenergy, biochar, or other value-added products could significantly enhance the sustainability and profitability of sugarcane industries. For instance, the conversion of bagasse into bioplastics or building materials could open new revenue streams and reduce waste disposal issues.

There is also a pressing need for enhanced energy efficiency within sugarcane biorefineries. Innovations in energy recovery and reuse systems could drastically reduce the energy consumption and greenhouse gas emissions of these facilities. Research into integrating solar power or other renewable energy sources directly into the processing plants could further reduce their carbon footprint. Lastly, there is an opportunity to strengthen regulatory frameworks to better support sustainable practices. Developing clear, consistent, and enforceable regulations that incentivize sustainable practices and penalize unsustainable ones can help level the playing field and encourage more producers to adopt environmentally friendly methods.

In summary, while there are considerable barriers to implementing sustainable practices in sugarcane processing, the opportunities for innovation and improvement are vast and hold the potential to transform the industry significantly.

6 Concluding Remarks

The systematic review of the literature on sustainability in sugarcane processing reveals a multifaceted approach integrating environmental and economic perspectives. Studies have identified the potential of sugarcane residues for bioethanol production as a means to enhance profitability and sustainability. The valorization of waste and by-products is emphasized as a crucial step towards sustainable development and a circular bioeconomy, with technologies ranging from well-established to emerging ones. The environmental and socio-economic impacts of sugarcane cultivation practices have been assessed, highlighting the importance of yields, cultivation practices, and proximity to sugar mills in influencing sustainability outcomes. A framework for analyzing sugarcane agro-industry sustainability has been developed, incorporating a composite sustainability index to assist in decision-making (Aguilar-Rivera, 2019).

Techno-economic assessments and life cycle analyses (LCA) of integrated biorefineries have shown that scenarios with larger ethanol production or full integration of sugar and ethanol production present the best economic and environmental performances, respectively. The integration of biomass gasification and Fischer–Tropsch synthesis to sugarcane biorefineries has been proposed as a means to significantly reduce greenhouse gas emissions (Bressanin et al., 2020). The environmental and economic implications of integrating sugarcane ethanol and soybean biodiesel production have been evaluated, suggesting improvements in environmental performance and economic feasibility. The concept of eco-efficiency has been used to assess sugarcane biorefineries, with mechanized farming and cane trash utilization for power generation yielding the highest eco-efficiency. The challenges and opportunities for the sugar industry in adopting green management practices for sustainability have been discussed, with a focus on diversification and green technologies (Solomon et al., 2019). Lastly, the expansion of sugarcane ethanol production in Brazil has been scrutinized for its environmental and social challenges, with recommendations for sustainable biofuel production.

Future research should focus on the following areas to further develop the sustainability of sugarcane processing. It is necessary to continue in-depth research on the environmental impacts of the sugarcane processing process, especially in terms of water resource and soil protection. Developing and promoting more efficient, water-saving sugarcane cultivation and processing technologies can address the increasingly severe problem of water resource shortages. For example, optimizing irrigation systems by adopting drip and micro-spray irrigation technologies can reduce water waste. At the same time, research on soil protection and improvement technologies is needed to prevent soil degradation and maintain soil fertility.

The comprehensive utilization of sugarcane processing waste should be explored. By converting waste such as bagasse into bioenergy, fertilizers, and other high-value-added products, waste resources can be realized, and environmental pollution can be reduced. This not only alleviates the environmental burden but also brings additional economic benefits to enterprises. For instance, producing biofuels from bagasse can partially replace fossil fuels and reduce carbon emissions; processing bagasse into organic fertilizers can improve soil and promote sustainable agricultural development.

Research and development of more intelligent and digital sugarcane processing technologies are needed. By introducing advanced technologies such as the Internet of Things, big data, and artificial intelligence, the level of automation and refined management in the production process can be improved, enhancing resource utilization efficiency and production benefits. For example, real-time monitoring and data analysis can optimize production processes, reducing resource waste and energy consumption; using smart devices can increase production efficiency and product quality.

Strengthening the life cycle assessment of the sugarcane processing industry chain is crucial. By quantifying and evaluating the environmental and economic impacts of different links, a more scientific and operational sustainable development strategy can be formulated. For example, assessing the entire process from sugarcane planting to product processing, transportation, consumption, and waste disposal can identify the links with significant environmental impacts, formulate corresponding emission reduction and environmental protection measures, and optimize the sustainability of the entire industry chain.

Attention should be paid to changes in consumer demand for sustainable products, conducting related market research and consumer behavior analysis, and developing sustainable products that meet market demand to improve market competitiveness and brand value. For instance, by researching consumer preferences and purchasing behavior regarding green products, environmentally friendly and healthy sugarcane products can be developed, and effective marketing can enhance brand awareness and market share.

Through the exploration and practice of the above research and development directions, the sugarcane processing industry will be able to find a more balanced and sustainable development path between environmental protection and economic benefits. This not only contributes to the long-term development of the industry but also makes a positive contribution to the green transformation of global agriculture and the food industry.

Acknowledgements

We would like to express our gratitude to the two anonymous peer reviewers for their meticulous review and rigorous revision suggestions.

Conflict of Interest Disclosure

The authors affirm that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

References

Abnave V.B., 2021, Economic viability of sugarcane cultivation: a comparative analysis, Journal of Sugarcane Research, 10(2): 158-173.

https://doi.org/10.37580/JSR.2020.2.10.158-173

Aguilar-Rivera N., 2019, A framework for the analysis of socioeconomic and geographic sugarcane agro industry sustainability, Socio-Economic Planning Sciences, 66: 149-160.

https://doi.org/10.1016/j.seps.2018.07.006

Bressanin J.M., Klein B.C., Chagas M.F., Watanabe M.D.B., Sampaio I.L.D.M., Bonomi A., and Cavalett O., 2020, Techno-economic and environmental assessment of biomass gasification and fischer–tropsch synthesis integrated to sugarcane biorefineries, Energies, 13(17): 4576.

https://doi.org/10.3390/en13174576

Cherubin M.R., Carvalho J.L.N., Cerri C.E.P., Nogueira L.A.H., Souza G.M., and Cantarella H., 2021, Land use and management effects on sustainable sugarcane-derived bioenergy, Land, 10(1): 72.

https://doi.org/10.3390/land10010072

Chico D., Pahlow M., Willaarts B.A., Sinisgalli P., and Garrido A., 2022, An integrated approach to assess the water efficiency of introducing best management practices: an application to sugarcane mechanisation in Brazil, Water, 14(7): 1072.

https://doi.org/10.3390/w14071072

Khumla N., Sakuanrungsirikul S., Punpee P., Hamarn T., Chaisan T., Soulard L., and Songsri P., 2022, Sugarcane breeding, germplasm development and supporting genetics research in Thailand, Sugar Tech., 24(1): 193-209.

https://doi.org/10.1007/s12355-021-00996-2

Kumar I., Bandaru V., Yampracha S., Sun L., and Fungtammasan B., 2020, Limiting rice and sugarcane residue burning in Thailand: current status, challenges and strategies, Journal of Environmental Management, 276: 111228.

https://doi.org/10.1016/j.jenvman.2020.111228

Kusumawati A., and Alam S., 2021, Sustainable nutrient management in sugarcane fields, Journal of Global Sustainable Agriculture, 2(1): 36-43.

https://doi.org/10.32502/jgsa.v2i1.3855

Longati A.A., Lino A.R., Giordano R.C., Furlan F.F., and Cruz A.J., 2020, Biogas production from anaerobic digestion of vinasse in sugarcane biorefinery: a techno-economic and environmental analysis, Waste and Biomass Valorization, 11: 4573-4591.

https://doi.org/10.1007/s12649-019-00811-w

Marodiyah I., Wahyuni H.C., and Nurmalasari I.R., 2023, Green productivity in increasing the productivity of sugar cane farmers and reducing impacts on the environment, Indonesian Journal of Cultural and Community Development, 14(2): 954.

https://doi.org/10.21070/ijccd.v14i2.954

Rabelo S.C., de Paiva L.B.B., Pin T.C., Pinto L.F.R., Tovar L.P., and Nakasu P.Y.S., 2020, Chemical and energy potential of sugarcane, in sugarcane biorefinery, technology and perspectives, Academic Press, USA, Massachusetts, pp.141-163.

https://doi.org/10.1016/B978-0-12-814236-3.00008-1

Raza Q.U.A., Bashir M.A., Rehim A., Sial M.U., Ali Raza H.M., Atif H.M., and Geng Y., 2021, Sugarcane industrial byproducts as challenges to environmental safety and their remedies: a review, Water, 13(24): 3495.

https://doi.org/10.3390/w13243495

Rein P.W., 2019, Developments in sugarcane processing over the past 15 years, Sugar Industry/Zuckerindustrie, 144(8): 451-458.

https://doi.org/10.36961/si23453

Shukla S.K., Solomon S., Sharma L., Jaiswal V.P., Pathak A.D., and Singh P., 2019, Green technologies for improving cane sugar productivity and sustaining soil fertility in sugarcane-based cropping system, Sugar Tech., 21: 186-196.

https://doi.org/10.1007/s12355-019-00706-z

Silalertruksa T., and Gheewala S.H., 2020, Competitive use of sugarcane for food, fuel, and biochemical through the environmental and economic factors, The International Journal of Life Cycle Assessment, 25: 1343-1355.

https://doi.org/10.1007/s11367-019-01664-0

Solomon S., Quirk R., and Shukla S., 2019, Special issue: green management for sustainable sugar industry, Sugar Tech., 21: 183-185.

https://doi.org/10.1007/s12355-019-00711-2

Sydney E.B., de Carvalho J.C., Letti L.A.J., Magalhaes Jr A.I., Karp S.G., Martinez-Burgos W.J., and Soccol C.R., 2021, Current developments and challenges of green technologies for the valorization of liquid, solid, and gaseous wastes from sugarcane ethanol production, Journal of Hazardous Materials, 404: 124059.

https://doi.org/10.1016/j.jhazmat.2020.124059

Ungureanu N., Vlăduț V., and Biriș S.S., 2022, Sustainable valorization of waste and by-products from sugarcane processing, Sustainability, 14(17): 11089.

https://doi.org/10.3390/su141711089