Special issue “Biomass-based industry: Towards a sustainable development”

There is a growing concern about the environmental impact of the industrial and energetic sectors, which have been strongly dependent on fossil resources. Such dependence has caused an accelerated increase in the concentration of greenhouse gases in the atmosphere, contributing to global warming and the changes in worldwide weather patterns. Moreover, the continuous use of fossil sources causes a depletion in the availability of such non-renewable materials, reducing the opportunities for future generations to satisfy their basic needs. However, breaking this dependence on fossil resources is not easy since they are employed to produce a wide variety of derivatives such as fuels, chemicals, and energy, which are fundamental for the current lifestyle of a significant percentage of the world population.

Under such circumstances, biomass has been identified as a raw material with the potential to satisfy needs currently fulfilled through fossil sources. Biomass is the mass of all living beings. Thus, its composition includes carbon, as occurs with petroleum. Then, proper treatment can transform biomass into bio-based equivalents of petroleum derivatives. Moreover, biomass is renewable and widely available in different world regions. A fraction of the vegetable biomass is used as food; thus, its use for other applications is not adequate from an ethical perspective. However, another fraction is considered waste, including agricultural residues, organic municipal solid wastes, and industrial wastes. On the other hand, there are vegetable species that are not used as food sources or organisms that may generate compounds useful for society. Examples of these are the Jatropha species and the microalgal biomass. All these are examples of biomass whose composition has wide potential to obtain essential derivatives. Moreover, in the case of wastes, these are produced daily in high volumes. Their use as raw materials avoids inadequate disposal while generating valuable products, promoting the implementation of production schemes in a circular economy perspective.

Although the technologies to transform biomass into valuable products are already available, with some biorefineries currently operating in the world, there are still challenges that must be addressed. The most important one is related to economic factors. Bio-based products commonly have relatively high production costs, which are reflected in the final selling price. This may affect the implementation of a bio-based economy, mainly in countries with low incomes. Thus, research must continue to determine strategies to enhance the processes used for biomass conversion. For instance, fermentation-based processes usually have low yields and require relatively long periods to achieve their purpose. Thus, the development of modified organisms is an area of opportunity. Moreover, the purification of the products implies a high energy demand due to the highly diluted broths. Then, more efficient purification technologies are mandatory, together with processes with lower clean water needs, which is also reflected in the environmental impact of the process. The need for research from a multidisciplinary perspective is evident, as it intends to generate sustainable production schemes from an economic, environmental, and social point of view.

The main topics covered in this special issue include the development and assessment of conversion routes to transform the biomass into valuable products, either fuels, bioproducts, or energy. Such pathways include chemical, biological and thermal treatments. The issue is focused on the valorization of biomass waste through its transformation into valuable derivatives, discussing strategies to implement production schemes in a circular economy framework.

This special issue presents various proposals for using biomass as a source of bio-based derivatives. The wastes from buckwheat processing are presented as raw materials to produce diverse derivatives, including fertilizers, chemical products, and pharmaceutical products. The potential of using such raw materials is discussed, and the challenges for implementing the studied production schemes are analyzed. The potential of cheese whey as a raw material to produce protein, fats, and fertilizers is presented in another article. Here, a biotechnological route based on biomass degradation with black soldier fly larvae is proposed and assessed. The treatment of fruit and vegetable wastes is presented in another article, studying the fermentation of combinations of wastes to produce bioethanol for its use as fuel. An interesting report related to the conversion of bagasse from Agave is also presented in this issue. The biomass is pretreated by steam explosion and then transformed into propionic acid using a modified strain. Another manuscript studies, from a theoretical perspective, the gasification of solid biomass through two potential routes. The first route implies the direct gasification of the biomass. On the other hand, the second route implies the indirect gasification of the biomass with pyrolysis oil as an intermediate.

All the presented articles represent the efforts to enhance the current biomass conversion routes, aiming to promote the development of a sustainable industrial sector, worried not only about satisfying the current demands of humanity but also about ensuring the capability of covering the needs of future generations. It is a challenge that needs the contribution of all of society to be solved.

Fernando Israel Gómez-Castro: Conceptualization; writing – original draft. Arturo González-Quiroga: Conceptualization; writing – original draft. Alpaslan Atmanli: Conceptualization; writing – original draft.

The authors declare no conflicts of interest.