Techniques to Control Microbial Contaminants in Nonsterile Microalgae Cultivation
- PDF / 457,255 Bytes
- 10 Pages / 439.37 x 666.142 pts Page_size
- 67 Downloads / 189 Views
Techniques to Control Microbial Contaminants in Nonsterile Microalgae Cultivation Daniel Pleissner 1,2
1
& Astrid Victoria Lindner & Ranga Rao Ambati
3
Received: 13 March 2020 / Accepted: 12 August 2020/ # Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract
The aim of this mini-review with own results was an identification of techniques to suppress the growth of microbial contaminants under photo- and mixotrophic conditions. Techniques identified are the modification of environmental conditions, such as pH, oxygen, and nutrient concentrations, as well as the application of pulsed electric field, ultrasonication, and surfactants. In phototrophic cultivations, the mentioned techniques result in a decrease of number of predatory cells, but not in a complete removal. Measures to suppress the growth of contaminations (e.g., bacteria and fungi) in mixotrophic cultivations could not be identified. The co-cultivation of algae and fungi, however, was found to be beneficial for the utilization of unusual carbon compounds (e.g., phenolic compounds). Keywords Contamination . Xenic conditions . Heterotrophy . Phototrophic . Bioeconomy
Introduction Microalgal biomass allows the formation of various products of low (bioenergy) and high value (pharmaceuticals) [1, 2]. The ability of microalgae to use carbon dioxide and sunlight (phototrophy), organic waste streams (heterotrophy), or both (mixotrophy) [3] has been leading to the development of cultivation systems within the frame of bioeconomy. Due to light inhibition and light saturation, biomass concentration obtainable in phototrophic cultivation systems, such as open ponds and closed tubular systems, is rather * Daniel Pleissner [email protected]
1
Sustainable Chemistry (Resource Efficiency), Institute of Sustainable and Environmental Chemistry, Leuphana University of Lüneburg, Universitätsallee 1, C13, 21335 Luneburg, Germany
2
Institute for Food and Environmental Research e. V., Papendorfer Weg 3, 14806 Bad Belzig, Germany
3
Center of Excellence, Department of Biotechnology, Vignan’s Foundation for Science, Technology and Research (Deemed to be University), Vadlamu, Guntur, Andhra Pradesh di-522316, India
Applied Biochemistry and Biotechnology
limited [4]. Contrarily, using heterotrophic cultivation, which relies on organic carbon sources, up to 100 times higher biomass concentration can be achieved [5]. Even though pure and expensive organic nutrients, such as glucose and amino acids, were successfully substituted by hydrolysates of organic waste streams [6–8], sterilization of substrate and equipment is a major economic drawback. Sterilization, however, is necessary since bacteria with faster growth rates can outcompete algal strains [9]. In phototrophic cultivation systems, where the concentration of free organic carbon sources is negligible, the presence of bacteria is rather unproblematic. The cultivation of phototrophic algal cells, however, is threatened by the appearance of predators feeding on cells. Colpoda steinii,
Data Loading...
