Multi-Wavelength Based Optical Density Sensor for Autonomous Monitoring of Microalgae

A multi-wavelength based optical density sensor unit was designed, developed, and evaluated to monitor microalgae growth in real time. The system consisted of five main components including: (1) laser diode modules as light sources; (2) photodiodes as detectors; (3) driver circuit; (4) flow cell; and (5) sensor housing temperature controller. The sensor unit was designed to be integrated into any microalgae culture system for both real time and non-real time optical density measurements and algae growth monitoring applications. It was shown that the sensor unit was capable of monitoring the dynamics and physiological changes of the microalgae culture in real-time. Algae biomass concentration was accurately estimated with optical density measurements at 650, 685 and 780 nm wavelengths used by the sensor unit. The sensor unit was able to monitor cell concentration as high as 1.05 g·L−1 (1.51 × 108 cells·mL−1) during the culture growth without any sample preparation for the measurements. Since high cell concentrations do not need to be diluted using the sensor unit, the system has the potential to be used in industrial microalgae cultivation systems for real time monitoring and control applications that can lead to improved resource use efficiency.

[1]  S. Vaidyanathan,et al.  A simple, reproducible and sensitive spectrophotometric method to estimate microalgal lipids. , 2012, Analytica chimica acta.

[2]  D. Briassoulis,et al.  An experimental helical-tubular photobioreactor for continuous production of Nannochloropsis sp. , 2010, Bioresource technology.

[3]  A. Sciandra,et al.  An optical method for the rapid measurement of micromolar concentrations of nitrate in marine phytoplankton cultures , 1999, Journal of Applied Phycology.

[4]  Teresa M. Mata,et al.  Microalgae for biodiesel production and other applications: A review , 2010 .

[5]  S. Lippemeier,et al.  A photobioreactor system for computer controlled cultivation of microalgae , 2005, Journal of Applied Phycology.

[6]  F. Malcata,et al.  On‐Line Determination of Biomass in a Microalga Bioreactor Using a Novel Computerized Flow Injection Analysis System , 2002, Biotechnology progress.

[7]  Robert E. Jinkerson,et al.  Genetic Engineering of Algae for Enhanced Biofuel Production , 2010, Eukaryotic Cell.

[8]  Hui Shen,et al.  Basic Culturing Techniques , 2007 .

[9]  H. Oh,et al.  Rapid method for the determination of lipid from the green alga Botryococcus braunii , 1998 .

[10]  Y. Chisti.  Biodiesel from microalgae. , 2007, Biotechnology advances.

[11]  W. Barclay,et al.  Heterotrophic production of long chain omega-3 fatty acids utilizing algae and algae-like microorganisms , 1994, Journal of Applied Phycology.

[12]  Razif Harun,et al.  Bioprocess engineering of microalgae to produce a variety of consumer products , 2010 .

[13]  A. Solovchenko,et al.  Stress-Induced Changes in Optical Properties, Pigment and Fatty Acid Content of Nannochloropsis sp.: Implications for Non-destructive Assay of Total Fatty Acids , 2011, Marine Biotechnology.

[14]  Chun-Chong Fu,et al.  Simultaneous estimation of chlorophyll a and lipid contents in microalgae by three-color analysis. , 2008, Biotechnology and bioengineering.

[15]  Yuan-Kun Lee,et al.  Determination of biomass dry weight of marine microalgae , 1997, Journal of Applied Phycology.

[16]  F. G. Fernández,et al.  Comparative analysis of the outdoor culture of Haematococcus pluvialis in tubular and bubble column photobioreactors. , 2006, Journal of biotechnology.

[17]  H. R. Gislerød,et al.  Real-time monitoring and automatic density control of large-scale microalgal cultures using near infrared (NIR) optical density sensors. , 2006, Journal of biotechnology.

[18]  Hideo Tanaka,et al.  Night biomass loss and changes in biochemical composition of cells during light/dark cyclic culture of Chlorella pyrenoidosa , 1996 .

[19]  Andrew J. Schmidt,et al.  Process Design and Economics for the Conversion of Algal Biomass to Hydrocarbons: Whole Algae Hydrothermal Liquefaction and Upgrading , 2014 .

[20]  Y. Bashan,et al.  Heterotrophic cultures of microalgae: metabolism and potential products. , 2011, Water research.

[21]  Maarten Boersma,et al.  Extraction of pigments and fatty acids from the green alga Scenedesmus obliquus (Chlorophyceae) , 2000, Aquatic Ecology.

[22]  Ondřej Komárek,et al.  A photobioreactor system for precision cultivation of photoautotrophic microorganisms and for high‐content analysis of suspension dynamics , 2008, Biotechnology and bioengineering.

[23]  Eric C. Henry,et al.  HANDBOOK OF MICROALGAL CULTURE: BIOTECHNOLOGY AND APPLIED PHYCOLOGY , 2004 .

[24]  A. Richmond,et al.  Optimization of a flat plate glass reactor for mass production of Nannochloropsis sp. outdoors. , 2001, Journal of biotechnology.