Publications (3)0 Total impact
Article: The soluble fraction of Solanum tuberosum enhances growth and pigmentation of the microalga Tetraselmis suecica under photoheterotrophic conditions[show abstract] [hide abstract]
ABSTRACT: The soluble fraction of Solanum tuberosum was utilized in the range 0.1–6.2 mg dry weight ml−1 to stimulate photoheterotrophic growth of axenic cultures of the marine microalga Tetraselmis suecica. The concentration of 5.0 mg ml−1 produced the highest cell density, 1.4 × 106 cells ml−1. This was 3.9 and 3.1 times higher than an autotrophic control (0.4 × 106 cells ml−1) and a photoheterotrophic control (0.5 × 106 cells ml−1). Using 3.7 mg dry weight of the S. tuberosum extract ml−1, the microalgae reached the highest contents of chlorophyll and carotenoids, 8.2 and 4.1 times higher than the autotrophic control. The marked enhancement of the photoheterotrophic growth of the microalgae by the addition of potato extract exceeded the growth stimulation caused by glucose and yeast extract. It suggests the feasibility of the use of potato biomass for the production of microalgal biomass and pigments.Bioresource Technology.
Article: Renewal rate of semicontinuous cultures of the microalga Porphyridium cruentum modifies phycoerythrin, exopolysaccharide and fatty acid productivity[show abstract] [hide abstract]
ABSTRACT: The red microalga Porphyridium cruentum was cultured semicontinuously at a nutrient concentration of 16 mmol N·l−1, and seven rates of daily renewal of the culture volume (2%, 5%, 10%, 20%, 30%, 40% and 50%) in order to establish the optimal conditions for the production of the biotechnologically valuable compounds phycoerythrin, sulfated polysaccharide and polyunsaturated fatty acids. The concentration of phycoerythrin was directly controlled by the availability of nitrogen in the culture medium, increasing with renewal rate while nitrogen was limiting and decreasing under nitrogen sufficient conditions, that were achieved with renewal rates higher than 10%. The concentration of total soluble exopolysaccharide followed a parabolic distribution with increasing renewal rates similar to that of phycoerythrin. On the other hand, the percentage of sulfatation of the excreted polysaccharide was stimulated at highest renewal rates and therefore with increasing nutrient availability and effective light intensity in the cultures. Total polyunsaturated fatty acid percentage remained stable with renewal rate, but the percentage of eicosapentaenoic acid (20 : 5n−3) increased with increasing renewal rates from 3% to 27% at the expenses of linoleic (18 : 2n−6) and arachidonic (20 : 4n−6) acids. Therefore, different strategies of cultivation should be applied for the production of each of the valuable compounds in semicontinuous cultures of P. cruentum.Journal of Fermentation and Bioengineering.
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ABSTRACT: Soluble fractions of germinated and non-germinated Solanum tuberosum tubers were evaluated as nutrient sources for the microalga Phaeodactylum tricornutum in batch and semicontinuous unialgal cultures. In batch cultures, the soluble fraction of germinated potato produced the highest microalgal density, 84·7 × 106 cell ml−1, compared with non-germinated potato, 66·4 × 106 cell ml−1 and the autotrophic control, 54·8 × 106 cell ml−1. The soluble fraction of germinated potato also increased cell and pigment productivities in semicontinuous cultures. Maximum cell productivities of 14·0 and 14·6 cell × 109 l−1 d−1 were obtained with renewal rates of 20 and 30% of the volume of the culture per day respectively. Maximum productivities of carotenoid (2·9 mg l−1 d−1) and chlorophyll (7·5 mg l−1 d−1) were obtained with a renewal rate of 40%. When cultured axenically, the non-germinated potato extract also produced a higher cell density of P. tricornutum than did the autotrophic control. The germinated potato constitutes an appropriate nutrient source for the production of microalgal biomass and pigments in mixotrophic conditions.Bioresource Technology.