Determination of fertilizing characteristics of three different microalgae cultivated in raceways in greenhouse conditions

Abstract

Microalgal biomass is rich source of macro elements such as nitrogen, phosphorus, potassium, and calcium. The purpose of this study was to investigate the different algae availability as fertilizer in agriculture. Therefore, three different microalgaes were selected for the experiment. Chlorella spp., Neochloris conjuncta and Botryococcus braunii cultures were grown in basal medium in the raceway which have the capacity of 1.5 tonnes. Experiment was ended when the required value of the number of cell was reached. Microalgaes were harvested by a centrifuge in 6000 rpm. Wet mass of microalgaes were dried in 65˚C at oven. Nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese, zinc, copper, boron, and organic matter were measured. Nitrogen values for Chlorella spp, Botryococcus braunii and Neochloris conjuncta microalgae were measured 5.45, 6.01, and 5.49 %, respectively. Microalgae can be used as nitrogen sources for plant growth and development due to high nitrogen levels. The concentrations of potassium were measured as 1.34, 0.94 and 1.05%. Organic matters were measured as 67.24, 64.15, and 64.65% for Chlorella spp, Botryococcus braunii and Neochloris conjuncta, respectively. Chlorella strain is currently used for fertilization purpose. However, this study showed that Neochloris conjuncta and Botryococcus braunii can used as fertilizer, as well.