Application of light-emitting diodes (LEDs) in cultivation of phototrophic microalgae: current state and perspectives

Abstract

The quality and regulation of the incident light is crucial in microalgae cultivation processes. Depending on wavelength, spectrum, and intensity, growth characteristics and biochemical composition of these organisms vary. With mainly fluorescent lamps (FL) used previously for illumination, such variabilities could not be studied adequately due to their broad emission spectrum. In contrast, light-emitting diodes (LEDs) emit a very narrow wavelength band and enable flexible photobioreactor designs due to their small size. This review provides a condensed overview on the application of LEDs in microalgal cultivation processes. It summarizes the current availability and applicability of LED technologies as an illumination source for research-focused photobioreactor systems. A particular focus is the use of narrow-wavelength LEDs to address fundamental as well as applied aspects of light color on algae biomass and value-added compound formation. In this respect, the application of internal and external illumination systems is reviewed together with trends in the industrial use of LED systems to intensify algae process efficiency.

A Review of Phosphorus Removal Technologies and Their Applicability to Small-Scale Domestic Wastewater Treatment Systems

“…Biofilms-based systems are of particular interest due to their ability to retain higher levels of biomass, resulting in space saving and greater resilience; both factors that are favorable in small-scale application. Coupled with the high levels of P-removal achieved at laboratory scale and the availability of low energy and easily controlled artificial lighting (Glemser et al, 2016), the use of phototrophic biofilm systems should be considered an attractive option for delivering P-removal at small-scale treatment systems.…”

Microalgae, old sustainable food and fashion nutraceuticals

“…Thus, new developments in lighting and its control are needed to make closed culture systems competitive. In this sense, irradiance oriented, optical fibres or diodes providing internal illumination have been used to enhance light intensity (Glemser et al, 2016;Sun et al, 2016). Designing surfaces with proper materials, functional groups or surface coatings, to prevent microalgal adhesion is also essential for solving the typical biofouling problems of PBRs (Zeriouh et al, 2017).…”

Emerging Technologies in Algal Biotechnology: Toward the Establishment of a Sustainable, Algae-Based Bioeconomy

“…Closed suspended growth PBRs, such as flat-plate, tubular, or bag reactors have increased operating control, better mixing, and less chance of contamination compared to open systems and are suitable for genetically modified organisms, but also have significantly higher capital and operational costs (Gupta et al, 2015). Closed systems can be operated using artificial light (at increased costs), which can be tailored to the specific algae to increase productivity (Schulze et al, 2014;Glemser et al, 2016). In addition, genetically modified organisms (GMOs) may have regulatory limitations that prevent them from growing in open systems where they can be released into the wild.…”