Growth of Chlorella vulgaris using different types of fertilizers under Laboratory Condition.

The study on the growth of Chlorella vulgaris using different types of fertilizers under laboratory condition was conducted at the laboratory room of the Mindanao State University-College of Fisheries Laboratory and Research Station (CFLRS), Siguel, General Santos City, for a period of 90 days with three (3) trials done. The objective of the study is to determine the growth of Chlorella vulgaris cultured using different fertilizers.

The result of the study showed that Black soil extract (Treatment I) resulted to high significance in the growth of Chlorella vulgaris, where it has attained its highest growth among the three treatments in all trials after 10 days of culture. Mean cell density of Chlorella vulgaris grown in Black soil extract was 25,758,000 cells/ml in the first trial, 10,050,000 cells/ml in the second trial and 13,150,000 cells/ml in the third trial. Followed by Chlorella vulgaris grown in Vermicast extract with mean cell density of 11,900,000 cells/ml in the first trial, 5,683,000 cells/ml in the second trial and 7,970,000 cells/ml in the third trial. Mean cell density of Chlorella vulgaris grown in Q fertilizer was found to be the lowest among the three treatments in all trials after 10 days of culture with 2,508,000 cells/ml in the first trial, 4,408,000 cells/ml in the second trial and 5,900,000 cells/ml in the third trial.

Analysis of variance (ANOVA) revealed that the growth of Chlorella vulgaris in Treatment I was significantly different from the other treatments (Vermicast extract and Q Fertilizer) at P > 0.05 and the specific growth rate (μ) was not significantly different to each treatment.

The study showed that the inorganic fertilizer (Q fertilizer) formulated for specific phytoplankton species is an efficient medium in obtaining high cell density of microalgae at a shorter culture period. Likewise, application of Black soil and Vermicast extract as organic fertilizers are found to be cheaper and contain nutrients that sustain growth of Chlorella vulgaris for longer culture duration.

Since the experiments were conducted under laboratory condition, it is recommended to conduct further trial or study in different dosages of Black soil extract, with the same amount of sterilized seawater, in outdoor conditions to collect more knowledge about this data. Also, to determine its effect in scale up condition, it is recommended to analyse the nutrient composition of the inoculation during culture period every phase, to know which nutrients have been consumed or exhausted during such phase.