Publicação
Screening of Pavlova sp. and scale-up to outdoor photobioreactors
| Resumo: | Microalgae are a promising source of several bioactive compounds such as proteins, lipids, carbohydrates, carotenoids and vitamins, which are valuable for commercial use and can be explored and used for diverse applications. Furthermore, microalgae are known producers of polyunsaturated (PUFA) omega-3 fatty acids, including eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids and, consequently, cultivation of microalgae as a supplement to marine animals is increasing. The marine microalgae Pavlova sp. is also widely used in aquaculture to feed crustacean, bivalves, and fish. In the present study, the growth of four Pavlova species (P. lutheri, P. gyrans, P. pinguis and P. granifera) was evaluated at lab-scale in order to select the most suitable species for outdoor and large-scale production. A preliminary trial comparing all strains showed that P. gyrans and P. pinguis had a higher final volumetric productivity, 0.087±0.005 g L-1 d -1 and 0.077±0.002 g L-1 d-1, respectively. In accordance, higher specific growth rates and maximum volumetric productivity were achieved by these species. The biochemical composition of all strains understudy was analyzed and the amount of PUFA (DHA and EPA) demonstrated to be the same for all Pavlova species. In addition, 30% of inoculum revealed to be the optimum inoculation rate to obtain higher global productivity when compared to 5, 10 and 20%. Furthermore, a screening outdoor assay was carried in 55 L flat panels using P. gyrans and P. pinguis. Both demonstrated a similar growth and global volumetric productivity, 0.058±0.007 and 0.079±0.019 g L-1 d-1, respectively. The FAME profile showed a higher PUFA content of 48% of total fatty acids (TFA) in P. gyrans, followed by 37% of TFA in P. pinguis. Outdoor cultures proved to have an increased lipids content and a higher level of EPA (30-40% of TFA) and DHA (9% of TFA), when compared with lab-scale production. Different types of outdoor photobioreactors (PBR) were used to investigate and compare their impact on P. pinguis scale-up: flat panel, tubular PBR and raceway pond. The results showed that flat panel was the system with the highest global productivity of 0.077 g L-1 d -1 and, similarly, the highest specific growth rate of 0.316 d-1. |
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| Autores principais: | Araújo, Joana Filipa da Silva |
| Assunto: | DHA EPA Growth optimization Industrial-scale production Pavlova Otimização do crescimento Produção industria |
| Ano: | 2019 |
| 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: | Microalgae are a promising source of several bioactive compounds such as proteins, lipids, carbohydrates, carotenoids and vitamins, which are valuable for commercial use and can be explored and used for diverse applications. Furthermore, microalgae are known producers of polyunsaturated (PUFA) omega-3 fatty acids, including eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids and, consequently, cultivation of microalgae as a supplement to marine animals is increasing. The marine microalgae Pavlova sp. is also widely used in aquaculture to feed crustacean, bivalves, and fish. In the present study, the growth of four Pavlova species (P. lutheri, P. gyrans, P. pinguis and P. granifera) was evaluated at lab-scale in order to select the most suitable species for outdoor and large-scale production. A preliminary trial comparing all strains showed that P. gyrans and P. pinguis had a higher final volumetric productivity, 0.087±0.005 g L-1 d -1 and 0.077±0.002 g L-1 d-1, respectively. In accordance, higher specific growth rates and maximum volumetric productivity were achieved by these species. The biochemical composition of all strains understudy was analyzed and the amount of PUFA (DHA and EPA) demonstrated to be the same for all Pavlova species. In addition, 30% of inoculum revealed to be the optimum inoculation rate to obtain higher global productivity when compared to 5, 10 and 20%. Furthermore, a screening outdoor assay was carried in 55 L flat panels using P. gyrans and P. pinguis. Both demonstrated a similar growth and global volumetric productivity, 0.058±0.007 and 0.079±0.019 g L-1 d-1, respectively. The FAME profile showed a higher PUFA content of 48% of total fatty acids (TFA) in P. gyrans, followed by 37% of TFA in P. pinguis. Outdoor cultures proved to have an increased lipids content and a higher level of EPA (30-40% of TFA) and DHA (9% of TFA), when compared with lab-scale production. Different types of outdoor photobioreactors (PBR) were used to investigate and compare their impact on P. pinguis scale-up: flat panel, tubular PBR and raceway pond. The results showed that flat panel was the system with the highest global productivity of 0.077 g L-1 d -1 and, similarly, the highest specific growth rate of 0.316 d-1. |
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