Publicação
Candida tropicalis as a promising yeast for olive mill wastewaters biodegradation and added-value compounds production
| Resumo: | Olive mill wastewaters (OMW), generated during olive oil production, have detrimental effects on the environment due to its high organic load and phenolic compounds content, which have antimicrobial effects. OMW are difficult to be biodegradable, but are a valuable resource of nutrients for microbial growth. In this study, the effect of initial cell concentration, nitrogen supplementation, pH and agitation rate on the growth of Candida tropicalis ATCC 750, consumption of OMW-components (reducing sugars, total phenols and chemical oxygen demand, COD) and production of added-value compounds (lipase, protease and microbial lipids) were studied in batch cultures in Erlenmeyer flasks and in bioreactor. In the flasks cultures it was observed that the degradation of total phenols and COD was positively affected by the supplementation of OMW with NH4Cl and low carbon/nitrogen (C/N) ratio. A significant enhancement of lipase production was obtained by the addition of urea, whereas protease synthesis was lower in such conditions. In optimized conditions in bioreactor experiments, Candida tropicalis was able to reduce 68 % of organic load (COD) and 39 % of total phenols of OMW, producing lipase (203 U·L-1) and protease (1105 U·L-1). Moreover, intracellular lipids were accumulated, most significantly under nitrogen-limited conditions, which is common in this type of wastewater. The high potential of C. tropicalis to detoxify OMW and to produce added-value compounds from it makes this process an alternative approach to other conventional processes of OMW treatment. |
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| Autores principais: | Dias, Bruna Filipa Silva |
| Assunto: | Olive mill wastewater Phenolic compounds Candida tropicalis Microbial lipids Lipase Protease Águas ruças Compostos fenólicos Candida tropicalis Lípidos microbianos Lipase Protease Engenharia e Tecnologia |
| Ano: | 2021 |
| 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: | Olive mill wastewaters (OMW), generated during olive oil production, have detrimental effects on the environment due to its high organic load and phenolic compounds content, which have antimicrobial effects. OMW are difficult to be biodegradable, but are a valuable resource of nutrients for microbial growth. In this study, the effect of initial cell concentration, nitrogen supplementation, pH and agitation rate on the growth of Candida tropicalis ATCC 750, consumption of OMW-components (reducing sugars, total phenols and chemical oxygen demand, COD) and production of added-value compounds (lipase, protease and microbial lipids) were studied in batch cultures in Erlenmeyer flasks and in bioreactor. In the flasks cultures it was observed that the degradation of total phenols and COD was positively affected by the supplementation of OMW with NH4Cl and low carbon/nitrogen (C/N) ratio. A significant enhancement of lipase production was obtained by the addition of urea, whereas protease synthesis was lower in such conditions. In optimized conditions in bioreactor experiments, Candida tropicalis was able to reduce 68 % of organic load (COD) and 39 % of total phenols of OMW, producing lipase (203 U·L-1) and protease (1105 U·L-1). Moreover, intracellular lipids were accumulated, most significantly under nitrogen-limited conditions, which is common in this type of wastewater. The high potential of C. tropicalis to detoxify OMW and to produce added-value compounds from it makes this process an alternative approach to other conventional processes of OMW treatment. |
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