Impacto del CO^sub 2^ sobre la densidad celular en seis cepas de microalgas marinas/Impact of CO^sub 2^ on cell density in six marine microalgae strains/Impacto do CO^sub 2^ na densidade celular em seis linhagens de microalgas marinhas

Abstract

As microalgae can capture CO2 easily from the environment, it is interesting to measure the amount and time control of the entry of this gas into microalgae mass culture, in order to increase cell density. The aim of this study was to evaluate the injection times of CO2 for biomass production that may lead to a higher cell density, it was also evaluated the pH variation without altering the quality of the crop. The work was made with six strains from the Germplasm Bank of the Instituto del Mar del Perú. There were performed cultures like 300L batch in a greenhouse, the cultivation time of the exponential phase lasted three days. The slope of the regression line parameters was analyzed to process data. The results showed that the cell density is inversely proportional to CO2 injection time cultivation. The higher cell density was obtained after 5min in different strains, except for strains Chaetoceros gracilis and Nannochloris maculate. Those microalgae got the highest density at 10 and 15min, respectively. The variation of pH tended toward acidity in a range from 8 to 4, without altering the cell density and the cultures remained free of contaminants. In conclusion, the results can establish the appropriate times of CO2 injection, which strengthen the exponential growth phase by increasing population density in 30% over the usual results of this phase.