Development And Validation Of A Near Infrared Specular Reflectance Flow Cell For Online Monitoring Of Microalgal Cultures

• Author / Creator

  Santiago Flores, Cloribel A

• Humankind is living in a world of rapid changes. Facts and situations that today seem to be permanent may be history tomorrow. Accordingly, in the future, energy sources maybe different, new, and more sustainable. Oil derived from microalgae is one of those promising options. Microalgae have been getting increasing attention during the past decade and especially in the most recent years as a result of their numerous advantages. Industrialization of microalgae is still in its early stages since microalgal processes possess diverse challenges that require further improvement. As a result, microalgal culture optimization is one area where plenty of work can be done. With this in mind, indisputably, a feasible, quick, and reliable monitoring system of the cultivation process is essential. Spectroscopy is a widely employed technique for online monitoring of a variety of chemical processes due to its capability to quickly gather information. This work explores the feasibility of monitoring the course of microalgal cultures using near infrared (NIR) spectroscopy. It is important to realize that in order to achieve this objective, several limitations intrinsic to microalgal processes need to be overcome. NIR spectroscopy reflectance was evaluated as a potential technique to monitor microalgal cultures. A NIR Specular Reflectance Flow Cell was successfully developed to allow for continuous monitoring, taking on account the technical requirements of the procedure and the distinctive characteristics of microalgal cultures. The capability of the flow cell to monitor microalgal cultures was investigated by determining glucose concentrations (10 – 100 g/L) in aqueous solutions and culture media (non-sterile and sterile) and quantifying biomass density (5 - 50 g/L, dry weight). Linear relationships between NIR absorbance and the concentrations of both biomass (dry weight) and glucose were observed. Oil estimation using whole algal cells was also explored but unfortunately, the response to the range of the evaluated oil concentration (0.4 – 0.9 g/L) was very small. To finalize the evaluation of the flow cell, the monitoring of 60 independent microalgal cultures was conducted to determine biomass density and possibly glucose. Simultaneous determination of biomass and glucose was not successful due to the large influence that biomass has on the NIR spectra.

• Subjects / Keywords

  • Microalgae
  • Near infrared
  • Flow cell

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3MG7G63V

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.