Fertilizer’s Effect on Growth of Chlorella in Sodium Phosphate

Abstract

Nutrient balance plays a key role in algae growth and biofuel potential. Our group looked at the different levels of nutrients, specifically sodium phosphate and fertilizer, which have an effect on Chlorella algal growth. We hypothesized that in the presence of 3 mL of sodium phosphate, algae cell density will increase as a result of increasing amounts of water-soluble fertilizer added to the solution until it reaches the plant’s threshold for nutrients. The fertilizer used was made of 30% nitrogen, 10% phosphorus, and 10% potassium. Upon constructing our photobioreactors we calculated the cell density of Chlorella using a hemocytometer. These photobioreactor bottles consisted of four bottles that held the control, 1% of the total solution volume of fertilizer added, 2% fertilizer by volume and 3% by volume. Our data was consistent with our original hypothesis, showing a positive relationship between cell growth and the use of fertilizer until a threshold point is reached, where cell density decreased as the fertilizer added by total solution volume reached 3%. These results can help to maximize power production using biofuels.