Modeling the impact of rotifer contamination on microalgal production in open pond, photobioreactor and thin layer cultivation systems

Abstract

Contamination of microalgal cultures by rotifers is known to cause large losses in productivity. The factors that control population dynamics of rotifers in microalgal cultures were studied in controlled contamination experiments in laboratory cultures. These experiments revealed that rotifer growth rates increase with microalgae biomass at low rotifer population densities and declines with rotifer biomass as the rotifer population approaches a carrying capacity. Experimental results were used to construct a model that describes the impact of rotifer contamination on three types of large-scale microalgal cultures. The results of this model indicate that rotifer contamination causes a complete loss in productivity in open pond and closed photobioreactor cultivation systems. In contrast, losses in productivity are limited in thin layer cascade reactors because the rotifer population cannot achieve a sufficiently high population density to cause a crash of the culture. These results suggest that different cultivation systems respond differently to rotifer contamination.

Microalgae: A Promising Source of Valuable Bioproducts

“…The main disadvantages of open cultivation systems are the complexity of process control, as well as the inability to organize a continuous cultivation process. High susceptibility to contamination by other microalgae and microorganisms, dependence on weather conditions (light, temperature) and daily temperature fluctuations make the open pond system unsuitable for large-scale culture [ 35 , 41 , 42 ].…”

Co-cultivation of microalgae in aquaculture water: Interactions, growth and nutrient removal efficiency at laboratory- and pilot-scale

“…vulgaris in the laboratory-scale cultivations. Open pond systems are prone to contamination by zooplankton [40] but thin layer cascade systems are less vulnerable than other types of systems thanks to higher operational biomass concentrations and higher volumetric productivity [42]. While keeping grazers at low levels is important for successful microalgae cultivation [18], their management is easy in a thin-layer cascade system because the complete culture can be harvested at regular intervals.…”

Microalgae: Cultivation Aspects and Bioactive Compounds

“…The open pond system, which has been used since the late 1950s due to its simplicity, is the most primitive system for their cultivation [34]. However, its susceptibility to contamination by other microalgae and microorganisms [37], and temperature variations throughout day/light periods [38] makes the open pond system not suitable for large scale culture [34].…”