Estudo comparativo da performance de crescimento de duas cepas da cianobactéria comercial Limnospira platensis (Spirulina) no Estado do Amapá

Abstract

The cyanobacterium Limnospira platensis (Spirulina) is widely recognized for its high protein potential and its diverse applications in the food industry, decarbonization, and other uses, both in Brazil and internationally. The main objective of this study was to compare the growth performance of two L. platensis strains, L. platensis Utex 1926 and L. platensis Varrenes, under different light intensities and culture medium conditions. Morphological and morphometric analyses were performed, which revealed significant structural differences, such as longer trichomes and open spirals in the Utex 1926 strain, in contrast to smaller, more compact trichomes and the presence of aerotopes in the Varennes strain. In this context, the presence of facultative calyptra observed in the Utex 1926 strain reinforces its close relationship to Limnospira, the clone of the type strain for the species, registered as PCC7345. Regarding the different Zarrouk medium dilution treatments and light intensity levels tested, significant differences were observed for the maximum productivity (Pmax) parameter between the strains and light conditions. Therefore, the Utex 1926 strain showed superior performance, reaching the highest maximum productivity of 95.3 org/mL/day/org under 10 watts, and maintaining high values of 73.3 under 20 watts. On the other hand, the Varennes strain did not show significant differences between light intensity levels, with Pmax of 23.6 and 12.5 for 10 and 20 watts. No significant differences were observed for the specific growth rate (µ) and doubling time (T2) parameters. Likewise, no significant differences were observed between the strains considering the culture dilution factor. We concluded that the Utex 1926 strain exhibited better growth performance, indicating greater production potential and standing out as a promising candidate for large-scale commercial cultivation in more dilute culture media. This study contributes significantly, as it provides support for optimizing L. platensis cultivation in Amapá, promoting the regional bioeconomy and strengthening sustainable production chains.