Publicação
Bioprocessing of main agro-industrial wastes of Portugal for protein enrichment and lignocellulolytic enzymes production
| Resumo: | Every year, large amounts of agro-industrial wastes are produced which are the most abundant renewable resources on earth. Economically, these residues can be used as low cost materials for the production of value-added compounds by decreasing production costs. From an environmental point of view, the reuse of this wastes in biotechnological processes can reduce its content in phenolic compounds and other toxic compounds which can deteriorate and degrade the environment when disposed in nature. One possible application for this type of waste is its use as animal feed. Frequently, the agroindustrial wastes are used as animal feed, however many times these wastes have a poor nutritional quality, mainly they have a low protein content and their digestibility is hard. These disadvantages can be avoided by solid-state fermentation (SSF) of the wastes. This study used wastes from the oil industry, the beer industry, and the wine industry. These residues were used as a solid substrate for the production of lignocellulolytic enzymes (cellulases and xylanases), to degrade partially the fibres of wastes and to increase the crude protein content of agroindustrial wastes in study. Firstly, it was performed a screening of the filamentous fungi through the inoculation of three different fungi, A. niger, A. uvarum and A.ibericus with each one of the different residues and it was evaluated the production of cellulases, xylanases, the increase of protein and the variation in lignocellulosic composition of solid. A. ibericus showed the best results in all wastes evaluated, and the SSF allowed to increase the protein content in all wastes. However, the lignocellulosic compounds were degraded in all cases. After selection of the fungi, it was performed an experimental design to evaluate the benefits of using mixtures of wastes in different proportions as solid substrate in SSF by A. ibericus. The optimum substrate was a mixture of brewery spent grain and vine-shoot trimmings which achieved and increase the protein content (16.3 %), xylanase (89.33 U/g), cellulose (3.46 U/g) and β -glucosidase (21.91 U/g) activities. At the end, it was performed a scaled up to a tray bioreactor with 500 of solid substrate. The results obtained were similar to flask experiments except to in cellulose and β -glucosidase activities that were lower. Through this study, it was possible to conclude that the SSF by A. ibericus is a suitable biotechnology process to increase the nutritional quality of agro-industrial wastes and to produce valueadded products as enzymes in the same low-cost process. |
|---|---|
| Autores principais: | Sousa, Daniel Filipe Martins Afonso Correia de |
| Assunto: | Engenharia e Tecnologia::Outras Engenharias e Tecnologias |
| Ano: | 2016 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Every year, large amounts of agro-industrial wastes are produced which are the most abundant renewable resources on earth. Economically, these residues can be used as low cost materials for the production of value-added compounds by decreasing production costs. From an environmental point of view, the reuse of this wastes in biotechnological processes can reduce its content in phenolic compounds and other toxic compounds which can deteriorate and degrade the environment when disposed in nature. One possible application for this type of waste is its use as animal feed. Frequently, the agroindustrial wastes are used as animal feed, however many times these wastes have a poor nutritional quality, mainly they have a low protein content and their digestibility is hard. These disadvantages can be avoided by solid-state fermentation (SSF) of the wastes. This study used wastes from the oil industry, the beer industry, and the wine industry. These residues were used as a solid substrate for the production of lignocellulolytic enzymes (cellulases and xylanases), to degrade partially the fibres of wastes and to increase the crude protein content of agroindustrial wastes in study. Firstly, it was performed a screening of the filamentous fungi through the inoculation of three different fungi, A. niger, A. uvarum and A.ibericus with each one of the different residues and it was evaluated the production of cellulases, xylanases, the increase of protein and the variation in lignocellulosic composition of solid. A. ibericus showed the best results in all wastes evaluated, and the SSF allowed to increase the protein content in all wastes. However, the lignocellulosic compounds were degraded in all cases. After selection of the fungi, it was performed an experimental design to evaluate the benefits of using mixtures of wastes in different proportions as solid substrate in SSF by A. ibericus. The optimum substrate was a mixture of brewery spent grain and vine-shoot trimmings which achieved and increase the protein content (16.3 %), xylanase (89.33 U/g), cellulose (3.46 U/g) and β -glucosidase (21.91 U/g) activities. At the end, it was performed a scaled up to a tray bioreactor with 500 of solid substrate. The results obtained were similar to flask experiments except to in cellulose and β -glucosidase activities that were lower. Through this study, it was possible to conclude that the SSF by A. ibericus is a suitable biotechnology process to increase the nutritional quality of agro-industrial wastes and to produce valueadded products as enzymes in the same low-cost process. |
|---|