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Otimização do crescimento de Chlorella sp. em meios de cultura preparados com xaropes obtidos de resíduos agroalimentar
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Abstract(s)
A indústria agroalimentar produz anualmente milhões de toneladas de subprodutos
durante o processamento da sua matéria-prima, sendo dispendioso tratá-los e pouco
rentável vendê-los para outras indústrias, este problema detém uma elevada
preocupação nas indústrias modernas.
O objetivo deste trabalho consistiu no aproveitamento de resíduos gerados na indústria
do vinho e do tomate, de forma a produzir substratos nutritivos (xaropes) para o cultivo
de Chlorella protothecoides. Este cultivo foi conduzido sob condições heterotróficas e
mixotróficas, visando a maximização da sua produtividade, com o objetivo de obter uma
fonte proteica alternativa e de qualidade para a alimentação animal. O meio ótimo de
crescimento foi determinado através da Metodologia de Superfície de Resposta (RSM)
usando um Desenho Composto Central (CCD) variando o volume de cada xarope de
forma a obter a produtividade máxima.
O acompanhamento do desenvolvimento das microalgas foi realizado com recurso a
amostragens diárias, de forma a elaborar as seguintes análises laboratoriais: peso seco,
densidade ótica, observação microscópica e medição de pH. A biomassa resultante do
meio de cultivo ótimo foi analisada quanto ao seu conteúdo de proteína, hidratos de
carbono e lípidos.
O estudo permitiu concluir que a combinação dos xaropes: lamas de tomate obtidas por
osmose inversa, massas da uva moscatel e borras fermentativas de uvas moscatel
favorece o crescimento da microalga obtendo-se uma produtividade em biomassa 54%
superior ao meio MSO, e 62% superior ao meio MCS. Relativamente ao teor proteico
na biomassa final registou-se um aumento de 87% em relação ao MCS e 20% para o
MCS revelando ser uma solução viável para obter um produto alternativo de elevado
teor proteico.
Realizou-se um estudo preliminar de crescimento da C. protothecoides num
fotobiorreator com maior capacidade volumétrica, em regime autotrófico, com o objetivo
de estudar a adaptabilidade da microalga ao equipamento, para posteriormente
aumentar o volume de cultura do meio ótimo determinado.
This work aims to use wastes generated in the wine and tomato industries to produce nutritious substrates for the cultivation of Chlorella protothecoides. This cultivation was carried out under heterotrophic and mixotrophic conditions, aiming to maximise productivity and obtain an alternative and quality protein source for animal feed. The optimal growth medium was determined through the Response Surface Methodology (RSM) using a Central Composite Design (CCD), varying the volume of each syrup to obtain maximum productivity. The development of microalgae was carried out using daily samples, to carry out the following laboratory analysis: dry weight, optical density by spectrophotometry, microscopical observation and pH measurements. The biomass resulting from the optimal cultivation medium was analysed for its protein, carbohydrate, and lipid content. This study concluded that the combination of these three syrups: tomato sludge obtained by reverse osmosis, muscatel grape pomace and fermentation lees from muscatel grapes, enhances the growth of microalgae, obtaining a biomass productivity 54% higher than the MSO medium, and 62% higher than the MCS medium. Regarding the protein content on the final biomass, there was an increase of 87% for MCS and 20% for MSO, proving to be a viable solution for obtaining an alternative product with a high protein content. A preliminary study was carried out on the growth of C. protothecoides in a photobioreactor with a larger volume capacity, in an autotrophic regime, with the aim of studying the adaptability of the microalgae to the equipment, to subsequently increase the culture volume of the optimum medium determined.
This work aims to use wastes generated in the wine and tomato industries to produce nutritious substrates for the cultivation of Chlorella protothecoides. This cultivation was carried out under heterotrophic and mixotrophic conditions, aiming to maximise productivity and obtain an alternative and quality protein source for animal feed. The optimal growth medium was determined through the Response Surface Methodology (RSM) using a Central Composite Design (CCD), varying the volume of each syrup to obtain maximum productivity. The development of microalgae was carried out using daily samples, to carry out the following laboratory analysis: dry weight, optical density by spectrophotometry, microscopical observation and pH measurements. The biomass resulting from the optimal cultivation medium was analysed for its protein, carbohydrate, and lipid content. This study concluded that the combination of these three syrups: tomato sludge obtained by reverse osmosis, muscatel grape pomace and fermentation lees from muscatel grapes, enhances the growth of microalgae, obtaining a biomass productivity 54% higher than the MSO medium, and 62% higher than the MCS medium. Regarding the protein content on the final biomass, there was an increase of 87% for MCS and 20% for MSO, proving to be a viable solution for obtaining an alternative product with a high protein content. A preliminary study was carried out on the growth of C. protothecoides in a photobioreactor with a larger volume capacity, in an autotrophic regime, with the aim of studying the adaptability of the microalgae to the equipment, to subsequently increase the culture volume of the optimum medium determined.
Description
Keywords
Resíduos agroalimentares Chlorella protothecoides Sustentabilidade Produtividade Crescimento heterotrófico e mixotrófico RSM Agriculture food wastes Chlorella protothecoides Sustainability Productivity Heterotrophic and mixotrophic conditions