Pigment production of <i>Nannochloropsis oculata</i> (eustigmatophyceae) under different colchicine concentration

The colchicine induction of Nannochloropsis oculata is potential strategy to augment the biomass and pigment because of its production is currently low. This approach is particularly appealing due to microalga’s recognized health and economic value. Therefore, this study aimed to systematically investigate the impact of colchicine induction that may cause polyploidy, on the biomass, pigment production, and DNA content of N. oculata. Optimal colchicine induction was examined at concentrations of 0, 10, 100, 1,000, and 10,000 mg L−1 to over 24, 48, and 72 h incubation period. Subsequent investigations were conducted at 48 h treatment duration, which was determined as optimal based on preliminary experiments. Microalgae were cultivated under controlled conditions using sterilized seawater, a continuous light source, and aeration with nutrient supplementation. The results showed that the group subjected to colchicine induction at the lowest concentration over 48 h showed the greatest cell size, DNA content, chlorophyll, and carotenoid levels. Induction at 1,000 mg L−1 for the same 48-h period increased biomass and pigment production while cell size remained unaltered. The results suggested that applying colchicine might result in more giant cell and genome size in N. oculata, indicative of potential polyploidy. A dose of 1,000 mg L−1, while failing to cause changes in genome size, facilitated the augmentation of pigment and biomass production. These characteristics provided opportunities for further study and exploitation.