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One of the bottlenecks related to the extraction of protein from lignocellulosic biomass is the development of an efficient, selective, economical, and environmentally friendly process. This study investigated the reduced-pressure alkaline pretreatment (RPAP) as an innovative approach for protein extraction from brewer's spent grain (BSG). Experiments were carried out at different temperatures (30–70 °C), pressures (150–1025 mBar), times (1–7 h), and NaOH concentrations (20–180 mM) to obtain a high-yield and selective protein extraction associated with low CO2 emissions and high processing capacity per batch. Protein concentration, total CO2 emissions per protein extracted, selectivity (related to sugars), and processing capacity were the responses considered for optimization. The optimum condition (T = 70 °C; P = 455 mBar, t = 1 h, and [NaOH] = 180.00 mM) was able to extract 80% of the total protein present in BSG composition. This condition was also selective (76.8%) and had a low carbon footprint (0.43 g CO2 g protein extracted−1). Glutamic acid was the most abundant amino acid in both raw BSG (22.9%) and protein hydrolysate (23.4%), followed by leucine (9.3% and 7.0%, respectively), proline (8.3% and 11.2%, respectively), and aspartic acid (8.8% and 7.6%, respectively). RPAP was demonstrated to be an efficient and sustainable technology for protein extraction from BSG. This opens up new opportunities for BSG and other protein-rich lignocellulosic materials valorization in a biorefinery.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais This research aims at both total and partial oxypropylation of lignocellulosic residues found in the Brazilian city of Uberlândia-MG, such as: mango pit, soybean skin, sugar cane straw, corn straw, corncob and from bacterial cellulose as well, in order to obtain two products: i) a viscous polyol; and ii) a fibrous solid residue superficially modified by grafting a thermoplastic polymer layer poly(propylene oxide). The raw materials, as well as the oxypropylated products obtained, were characterized after being submitted to several techniques, such as: X-Rays Diffraction, Infrared Spectroscopy under Fourier Transform, Thermogravimetric analyses, Scanning Electron Microscopy, Content of Solid residue superficially modified, Content of Homopolymer of propylene Oxide, Hydroxyl Index and Viscosity. In order to obtain a viscous polyol from sugar cane straw, it is indicated: 15 ml of propylene oxide in temperature of 200 °C, because this condition showed the lowest content of solid residue superficially modified, and indicated better results during the conversion of the raw material tested. After both total and partial oxypropylation of lignocellulosic residues we could obtain: i) both polyol compound poly(propylene oxide) and molecules from this lignocellulosic residue (cellulose, lignin and polyoses); ii) a solid residue fibrous superficially modified by grafting a thermoplastic polymer layer of poly (propylene oxide), also verified during the partial oxypropylation of bacterial cellulose. The results of thermogravimetry, Spectroscopy in Infrared and X-Ray Diffraction, in addition to Scanning Electron Microscopy pictures harmonized themselves and confirmed the presence of a thermoplastic superficial layer in the cellulose fibers from the residues and bacterial cellulose superficially modified by partial oxypropylation . The materials developed in this study can be converted into high added value products of industrial interest such as obtaining a self-reinforced composite as well as rigid polyurethane foams. Moreover, the oxypropylation can be an alternative to enlarge the range of applications of these renewable sources. In addition, it can also contribute to green Chemistry for it represents a simple process and does not generate by-products: all the material inserted into the reactor is converted into the desired final product. O presente trabalho de pesquisa tem como objetivo a oxipropilação total e parcial de resíduos lignocelulósicos obtidos na região de Uberlândia-MG, a saber: caroço de manga, casca de soja, palha de cana-de-açúcar, palha de milho e sabugo de milho e também da celulose bacteriana de forma a obter dois produtos: i) um poliol viscoso; e ii) um resíduo sólido fibroso modificado superficialmente com a enxertia de uma camada de polímero termoplástico de poli(óxido de propileno). Os materiais brutos e os oxipropilados obtidos foram caracterizados após serem submetidos a diversas técnicas de análises, quais sejam: Difração por Raios X, Espectroscopia em Infravermelho com Transformada de Fourier, Análise Termogravimétrica, Microscopia Eletrônica de Varredura, Teor de Resíduo Sólido Modificado Superficialmente, Teor de Homopolímero de Óxido de Propileno, Índice de Hidroxila e Viscosidade. Para obtenção do poliol viscoso, indica-se o resíduo de palha de cana-de-açúcar e as condições do experimento 3, qual seja: 15 ml de óxido de propileno à temperatura de 200 °C, sendo esta a condição que apresentou baixo teor de resíduo sólido modificado superficialmente (8,5%) e menor custo. Por meio da oxipropilação total e parcial dos resíduos lignocelulósicos provindos da região de Uberlândia-MG, obtivemos: i) poliol composto de copolímeros de poli(óxido de propileno) e moléculas provenientes deste resíduo lignocelulósico (celulose, lignina e polioses); ii) um resíduo sólido fibroso modificado superficialmente com a enxertia de uma camada de polímero termoplástico de poli(óxido de propileno), também verificado para a oxipropilação parcial da celulose bacteriana. Os resultados da Termogravimetria, da Espectroscopia em Infravermelho e da Difração de Raios X, além das imagens de Microscopia Eletrônica de Varredura mantiveram-se harmônicos e confirmaram a presença da camada termoplástica superficial nas fibras de celulose dos resíduos e celulose bacteriana modificados superficialmente pela oxipropilação parcial. Os materiais desenvolvidos neste trabalho podem ser convertidos em produtos com alto valor agregado de interesse industrial, como a obtenção de compósito autorreforçado, assim como espumas rígidas de poliuretano. Ademais, a oxipropilação pode ser uma alternativa para ampliar as aplicações dessas fontes renováveis, além de contribuir com a Química verde por ser um processo simples que não gera subprodutos: todo o material inserido no reator é convertido no produto final desejado. Doutor em Química