Correlation Between Paddle Wheel Operation Time with Microalgae (Nannochloropsis sp.) Growth Rate and Lipid Contents in Open Raceway Ponds

Welmar Olfan Barat,Dietriech G Bengen,Mujizat Kawaroe

doi:10.20884/1.oa.2017.13.1.76

Abstract

Nannochloropsis sp. is one of microalgaes species with high lipid content, so it has great potential to be used as the source of biofuel. One of the microalgae cultivation system in mass scale is open raceway ponds. Problems faced in microalgae cultivation with open raceway ponds system are low productivity and the high production cost, especially high electrical energy for operating paddle wheel machine. This research studies about efficiency and effectiveness level of the cultivation system with open raceway ponds through the analysis of correlation between operational duration of the paddle wheel with growth rate and lipid content from Nannochloropsis sp.. The highest density is 530x106 cell/ml found in treatment of 45min/h. The highest growth rate is 0,45/days Which also found in the treatment of 45min/h but the treatment 45min/h is only able to survive until 12 days. The highest productivity of dry biomass is 0,25 g/L/day found in treatment of 45min/h. Meanwhile, the highest lipid content contained on treatment 15min/h is 5,19%DCW. Dominant fatty acids for all treatments are palmitic acids. The best treatment related to the use of the paddle wheel machine is 15min/h.

Highlights

The research development of renewable energy has increasingly conducted to answer the challenges of the energy crisis
This condition is suspected during the cultivation, the controls were not carried out with paddle wheel stirring, so deposition occurred at low level of sunlight penetration into the waters of the column led to the no optimal photosynthesis process has impacted the immediate death
Conditions that occurrred in the treatment of 45min/h system result to the increased rate of water movement that exceed the optimum limits for microalgae growth in cultivation system of open raceway ponds, and caused many waves and bubbles which results in refraction of sunlight into the column

Summary

Introduction

The research development of renewable energy has increasingly conducted to answer the challenges of the energy crisis. The effort of providing alternative fuels becomes very important, including through biofuels. Research development of raw material has been conducted a lot such as crude palm oil (CPO) from Palm oil, corn, soybean, canola, jatropha, coconut, and microalgae with production capacity of the plant as much as 172 litres per hectare of corn, soy 446 litres per hectare, olive oil 1190 liters per hectare, a distance of 1892 liters per hectare, nuts 2689 liters per hectare, Palm 5.950 liters per hectare, and microalgae 58.700 liters per hectare (Chisti, 2007). Microalgae is the marine plants that is able to grow up in a very short time. Is able to grow quickly and have a high level of tolerance towards environmental pressure. Some environmental conditions that can affect the microalgae growth among are temperatures, the quality and quantity of nutrients, light intensity, the degree of acidity (pH), aeration (source of CO2) and salinity (Kawaroe et al, 2010)

Methods

Results

Conclusion