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Based on a circular bioeconomy strategy, eucalypt wood fines rejected from a Kraft pulp line were used as starting material in a pilot-scaled fast-pyrolysis process. The bio-oil and its coproducts were characterized regarding their physical, chemical, and thermal aspects. We put in perspective their properties to bring forward considerations for applications on biofuels, materials, and precursors. The yields of the pilot-scaled fast-pyrolysis process reached interesting values even if compared with optimized laboratory conditions. The results indicated the highest heating values (22–27 MJ/kg) for bio-oil, char, and crust material. The higher water content of aqueous extract had a negative effect for its application as fuel. The lignin/carbohydrate ratio for the bio-oil (2.82) and aqueous extract (0.53) identified a higher concentration of lignin-derived compounds in the first, mainly syringyl units. Bio-oil and aqueous extract presented chemical compounds with many functionalities, such as syringaldehyde and levoglucosan, expanding their potential application for higher value-added products besides energy.

The aim of this study is to enhance the use of agro-industrial byproducts and to address the environmental concerns by a novel method of co-production of thermoplastic composites with a solid residue constituting biorefinery. Accordingly, the reuse of 10–30 wt. % solid residues (SRH) from the enzymatic hydrolysis of recycled paper sludge (PS) in the production of thermoplastic composites with polypropylene (PP) was investigated. Thermal properties, water absorption, tensile strength and morphology of the prepared composites were evaluated. Higher thermal stability, rougher and wetter surface, and characteristics of a brittle material were observed in PP-SRH composites in comparison to the pristine PS-PP composites and the neat PP. The water absorption increased with increasing amount of SRH, but in lower proportion compared to other common raw materials used in the preparation of composites. Use of SRH resulted in similar or better properties compared to the composites made with the unhydrolyzed paper sludge, suggesting that SRH has potential for recycling and utilization as filler in the development of thermoplastic composites.

With population growth and increasing industrialization, enormous amounts of agro-industrial wastes are being produced. Without proper use, these keep piling up leading to tremendous pressure on environmental safety. There is also considerable economic interest not only in the proper utilization of these wastes, but also in developing appropriate processes for this purpose. Sludge generated in pulp and paper mills is one of such solid wastes. Although several studies have investigated its reuse, it is still disposed mostly in landfills, leading to environmental pollution. Utilization of this waste could economically benefit for the pulp and paper sector. An innovative and potentially valuable solution seems to be converting it into ethanol, on which a considerable number of reports have published diverse reviews, even though improvements in the technology are still needed. Hence, this study attempts to provide an overview of all studies carried out so far, highlighting key scientific and technological barriers for scaling up and implementing the conversion process. Some suggestions for future research are given, while perspectives and projections point out that adoption of this process could be especially interesting for regions such as Europe and Asia, where the generation of sludge is high and the ethanol production capacity is still low.

Waste disposal from paper and pulp industry is of great environmental concern. Sludge from recycled paper mills favors colonization with different microbial species due to its chemical composition. In this environment, the microbiota can express enzymes that hydrolyze celluloses and hemicelluloses, such as cellulases, β-glucosidases, and xylanases. Understanding microbiota living in such disposal may give directions to what kind of enzymes or bioproducts may be possible to obtain from this microorganism and how to deal with the waste during the process. We have accessed microbial community associated with two steps in the recycled paper sludge generation by high-throughput DNA sequencing: fibrous residue, and wastewater sludge. Bacteroidetes, Proteobacteria and Firmicutes phyla represented more than 96% of the total. From the eukaryote perspective, Vorticella was the most frequent in fibrous residue samples while Acanthamoeba was the most common on wastewater sludge samples. Among the isolates cellulase activity was detectable only from fungi isolates. Half of the bacterial isolates presented xylanase activity, and most of them in high level of activity. Both a metabarcoding and culturing approaches are valuable tools for enzymatic screening in industrial waste disposal.

Finding innovative solutions to manage waste and to expand the production of biofuels are some of the current challenges. Pulp and paper sectors, including recycled paper mills, produce a large amount of solid wastes, such as wastewater sludge containing non-recyclable short fibres. This study aimed to: (1) characterize recycled paper sludge; (2) define conditions for enzymatic hydrolysis and (3) evaluate two processes for ethanol production from the sludge: separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF). The waste showed a very high content of ash (58 %), which negatively affected enzyme action. A commercial enzyme cocktail (Cellic® CTec2) was used for the saccharification, at 43 °C and 6 % dosage. The highest ethanol yield (55.7 %) with shorter residence time (72 h) resulted from the SSF process. The best performance using the SHF process yielded 45.8 % after 84 h. Despite the intermediate results, sludge from pulp and paper mills could be an attractive raw material due to its low price and not requiring a pretreatment step for delignification. This application could be especially interesting for regions where the generation of paper sludge is high and the ethanol production capacity is still low, such as Asia.

Functional foods are one of new trends for the food industry and nanotechnology can be useful for enrichment of food or parts of the food with natural bioactive compounds. Besides the introduction of nutraceuticals into food, nanotechnology may allow the protection of the functional compounds against degradation, and, furthermore, improve their bioavailability. Nanocapsules of biomacromolecules can be employed for entrapment of sensitive hydrophobic nutraceuticals with partial protection against photochemical degradation to enrich food products without modifying sensory properties. Insoluble fibers from plants can be employed to improve intestinal tract and decrease cholesterol and sugar absorption into blood. Besides, nanoparticles or nanofibers would be useful for jellification or emulsions, which have great potential for beverage applications associated with delivery of bioactives. However, some nanomaterials, mainly inorganic crystalline ones, may have toxic effects in the body and proper steps should be taken before recommending them for industrial applications. There are many processes for obtaining nanomaterials, which may belong to either bottom-up and top-down approach. This chapter focuses on some of these aspects along with some perspectives.

Biomassas lignocelulósicas, como resíduos agrícolas e florestais, podem servir de matriz carbônica para a fermentação e obtenção do etanol de segunda geração (2G). Porém, os açúcares fermentescíveis não estão prontamente disponíveis, precisando ser liberados por operações adicionais de pré-tratamento e hidrólise. Paralelamente, substâncias químicas com potencial efeito inibitório ao metabolismo microbiano também são formadas e podem comprometer a produtividade e o rendimento global do processo. Esse estudo teve como objetivo avaliar a influência de vanilina, ácido acético, ácido vanílico e ácido 4-hidroxibenzoico na fermentação de glicose pela levedura Saccharomyces cerevisiae JP1. O cultivo ocorreu em meio sintético composto por nutrientes e 40 g.L-1 de glicose, inibidor em diferentes concentrações e 3% (v/v) de inóculo obtido em meio YPD líquido. O experimento foi conduzido a 30 °C e 150 rpm por 22 h. Amostras foram coletadas periodicamente para monitoramento da multiplicação celular e consumo de substrato, bem como quantificação de etanol no final do procedimento. Os resultados indicaram que vanilina (0,1; 0,5; 1,0 e 1,5 g.L-1) e ácido vanílico (0,1; 0,5 e 1,0 g.L-1) inibiram o crescimento da levedura em uma extensão diretamente proporcional à concentração inicial destes no meio fermentativo. O ácido 4-hidroxibenzoico apresentou, em média, 25% de toxicidade em relação ao crescimento celular, independente das quantidades estudadas (0,1; 0,5 e 1,0 g.L-1). Total inibição do crescimento celular, consumo de glicose e produção de etanol foi observada no meio com ácido acético em concentrações iguais ou superiores a 3,5 g.L-1.