Olive mills generate a large amount of waste that can be revaluated. This work aim to improve the production lignocellulolytic enzymes by solid-state fermentation using ultrasounds pretreated olive mill wastes. The composition of olive mill wastes (crude and exhausted olive pomace) was compared and several physicochemical characteristics were significantly different. The use of both wastes in SSF was evaluated and a screening of fungi for xylanase and cellulase production was carried out. After screening, the use of exhausted olive pomace and Aspergillus niger led to the highest enzyme activities, so that they were used in the study of ultrasounds pre-treatment. The results showed that the sonication led to a 3-fold increase of xylanase activity and a decrease of cellulase activity. Moreover, the liquid fraction obtained from ultrasounds treatment was used to adjust the moisture of solid and a positive effect on xylanase (3.6-fold increase) and cellulase (1.2-fold increase) production was obtained.
In recent years, the interest to find alternative extraction methods has increased. Extraction of natural phenolics by enzymes produced during solid-state fermentation (SSF) is a useful and novel technique environmentally friendly. On the other hand, agro-industrial wastes are an excellent source of natural antioxidants as phenolics. The aim of the work was to evaluate the increase of antioxidant compounds extraction from agro-industrial wastes after SSF and to relate it to the production of lignocellulolytic enzymes. Several filamentous fungi were evaluated as candidates to increase the extraction of antioxidant compounds by solid-state fermentation of wineries, olive mill and brewery wastes. Fermented and unfermented agro-industrial wastes were extracted with water and lignocellulolytic enzymes, total phenolic compounds and antioxidant activity were determined in the extract. The maximum xylanase and cellulase activities were achieved by A. ibericus strains using brewer´s spent grain (BSG) as substrate and ranged from 300 to 313 U xylanase/g and 51-62 U cellulase/g. The best producer of β-glucosidase was A. niger CECT2088 using BSG as substrate (94 ± 4 U/g). The results of extraction of phenolic compounds revealed a higher extraction by SSF in olive mill wastes followed by winery wastes. In the same form, the maximum increase of antioxidant activity was achieved by SSF of exhausted olive pomace by Rhizopus oryzae MUM 10.260, increasing 12.9-fold in relation to unfermented waste. In addition, the production of enzymes, the extraction of phenolic compounds and the increase of antioxidant activity were related by principal component analysis. The first component grouped the BSG along with maximum enzymes production, the second component related positively the production of enzymes and the extraction of phenolic compounds and the increase of antioxidant activity. SSF proved to be an innovative environmentally friendly process that can improve the extraction of antioxidant compounds and simultaneously to produce lignocellulolytic enzymes from different agro-industrial wastes.
Agricultural, forestry, and food industries produce large amounts of lignocellulosic wastes every year. Land disposal of these residues without proper treatment leads to environmental pollution and negative health effects. The recent advances in valorization of agro-industrial wastes by the production of lignocellulolytic enzymes under solid-state fermentation (SSF) are reviewed. SSF is a promising technology to produce lignocellulolytic enzymes. However, the large-scale feasibility is the main challenge of SSF being the control of operational parameters and adequate reactor design the first locks. The current and future trends of SSF bioreactors for lignocellulolytic enzyme production are summarized. SSF allows the production of lignocellulolytic enzymes with high stability at different temperatures and pH, improving their applicability in different industrial settings.
RESUMO: Objetivou-se verificar o efeito da sanitização, contaminação experimental bacteriana e da refrigeração na perda de peso de ovos, durante o período de armazenamento de 30 dias. Foram utilizados 96 ovos, os quais pesados a cada três dias. O delineamento utilizado foi em blocos casualizados em esquema fatorial 2 x 2 x 2 (sanitização x contaminação x temperatura de armazenamento), com seis repetições e um ovo a unidade experimental. A sanitização dos ovos foi realizada com a lavagem com água morna contendo clorhexidina 20% e teor ativo 8% de cloro. Após, os ovos foram contaminados na casca, pelo manuseio por 10 segundos, com 1,5 x 10 5 unidades formadoras de colônias (UFCs) de Pseudomonas aeruginosa/mL de solução e permaneceram armazenados a 5 o C ou 25 o C por 30 dias. Constatou-se que a refrigeração manteve a qualidade interna dos ovos, mesmo quando houve contaminação na casca com inóculo de Pseudomonas aeruginosa. Concluiu-se que a refrigeração retarda a perda de peso e proporciona melhor qualidade interna, física e química de ovos, durante os 30 dias de armazenamento, independente da contaminação e do processo de sanitização.
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