RESUMO
Carotenoids are natural pigments that can be produced through biotechnological processes. However, the costs are relatively high and can be minimized by using lower-cost substrates as alternative nutrient sources. The fed-batch fermentation is one of the techniques used to obtain a high biomass concentration and/or maximum production. Thus, the aim of this work is to produce carotenoids in batch and fed-batch fermentation with the yeast Rhodotorula mucilaginosa CCT 7688 using agroindustrial byproducts in the culture medium. Carotenoid production was increased using experimental designs, which modified the concentration of the agroindustrial medium. In batch production the highest concentrations of total carotenoids (1248.5 µg/L) and biomass (7.9 g/L) were obtained in the medium containing 70 g/L sugar cane molasses and 3.4 g/L corn steep liquor at 25 °C and 180 rpm in 168 h, demonstrating an increase of 17% when compared to the standard yeast malt medium (1200 µg/L). In the fed-batch production, different feeding strategies were tested with 30 g/L sugar cane molasses and 6.5 g/L corn steep liquor, reaching a total carotenoid production of 3726 µg/L and biomass concentration of 16 g/L. Therefore, the strategy of the fed-batch process resulted in an increase in the carotenoid production of approx. 400% compared to that in the batch process (740.3 µg/L). Thus, the R. mucilaginosa strain has the potential to produce carotenoids in agroindustrial medium.
RESUMO
No presente estudo, utilizando melaço de cana-de-açúcar como única fonte de carbono para Agrobacterium radiobacter k84 foi obtido, em processo fermentativo, um biopolímero composto por carboidratos (35%), proteínas (15%) e minerais (40%). O rendimento do processo foi de 10 g.L-1do biopolímero que apresentou elevada solubilidade em água, pH neutro em solução aquosa e baixa atividade de água (0.52). As análises em Microscopia Eletrônica de Varredura revelaram microestrutura característica de um sólido amorfo, com partículas de formas irregulares e tamanhos variáveis. Na avaliação das propriedades tecnológicas, o biopolímero mostrou viscosidade à temperatura ambiente a partir da concentração 0.5% em solução aquosa, atividade geleificante em solução a 2%, atividade emulsificante (56.11±0.78%) e estabilizante (98.02±1.39%). Os resultados sugerem o biopolímero de Agrobacterium radiobacter k84 como um candidato promissor para uso industrial.
In this study, a biopolymer composed of carbohydrates (35%), protein (15%) and minerals (40%) was obtained through fermentation using sugar cane molasses as the sole carbon source for Agrobacterium radiobacter k84. The process yield was 10 gL-1 of biopolymer, which showed high solubility in water, neutral pH in aqueous solution and low water activity (0.52). The analysis in Scanning Electron Microscopy revealed microstructure characteristic of an amorphous solid, with particles of irregular shapes and sizes. In the evaluation of technological properties, the biopolymer showed formation of viscous solutions at room temperature from concentration of 0.5% in aqueous solution, gelling activity in solution at 2%, emulsifying (56.11±1.39%) and stabilizing activity (98.02±0.78%). The results suggest that the biopolymer from Agrobacterium radiobacter k84 is a promising candidate for industrial use.
Assuntos
Biopolímeros , Melaço , Agrobacterium tumefaciens , SaccharumRESUMO
In this study, a biopolymer composed of carbohydrates (35%), protein (15%) and minerals (40%) was obtained through fermentation using sugar cane molasses as the sole carbon source for Agrobacterium radiobacter k84. The process yield was 10 gL-1 of biopolymer, which showed high solubility in water, neutral pH in aqueous solution and low water activity (0.52). The analysis in Scanning Electron Microscopy revealed microstructure characteristic of an amorphous solid, with particles of irregular shapes and sizes. In the evaluation of technological properties, the biopolymer showed formation of viscous solutions at room temperature from concentration of 0.5% in aqueous solution, gelling activity in solution at 2%, emulsifying (56.11±1.39%) and stabilizing activity (98.02±0.78%). The results suggest that the biopolymer from Agrobacterium radiobacter k84 is a promising candidate for industrial use.
No presente estudo, utilizando melaço de cana-de-açúcar como única fonte de carbono para Agrobacterium radiobacter k84 foi obtido, em processo fermentativo, um biopolímero composto por carboidratos (35%), proteínas (15%) e minerais (40%). O rendimento do processo foi de 10 g.L-1 do biopolímero que apresentou elevada solubilidade em água, pH neutro em solução aquosa e baixa atividade de água (0.52). As análises em Microscopia Eletrônica de Varredura revelaram microestrutura característica de um sólido amorfo, com partículas de formas irregulares e tamanhos variáveis. Na avaliação das propriedades tecnológicas, o biopolímero mostrou viscosidade à temperatura ambiente a partir da concentração 0.5% em solução aquosa, atividade geleificante em solução a 2%, atividade emulsificante (56.11±0.78%) e estabilizante (98.02±1.39%). Os resultados sugerem o biopolímero de Agrobacterium radiobacter k84 como um candidato promissor para uso industrial.