Establishment of high-cell-density heterotrophic cultivation of Poterioochromonas malhamensis contributes to achieving biological control of Microcystis

Effects of Nutritional Mode on the Physiological and Biochemical Characteristics of the Mixotrophic Flagellate Poterioochromonas malhamensis and the Potential Ecological Implications

“…However, its application values have been restricted greatly by the undeveloped mass cultivation methods commonly used for P. malhamensis . In this study, the maximum cell concentration of P. malhamensis was in the order of magnitude of 10 7 cells mL −1 , but we have established a chemoheterotrophic fermentation technology for cultivation of P. malhamensis using the axenic seed culture, which yields a maximum cell concentration and dry weight of P. malhamensis under optimal fermentation conditions of 3 × 10 8 cells mL −1 [ 40 ] and 32.8 g L −1 [ 38 ], respectively.…”

“…The present study has shown that the transformation of nutritional modes can alter the biochemical composition of the mixotrophic flagellate P. malhamensis and, as a result, affect the grazing ability of its predator Paramecium caudatum . Moreover, a recent study has shown that the grazing ability of P. malhamensis on its prey Microcystis aeruginosa also varies depending on the nutritional mode of the P. malhamensis [ 40 ]. These studies imply that changes in environmental nutrient resources would greatly affect the flow directions within food chains centered on mixotrophic flagellates.…”

A systematic review of the predatory contaminant Poterioochromonas in microalgal culture

“…Adjustment of the pH or the concentration of dissolved oxygen or carbon dioxide (CO 2 ) in the culture medium has also been studied as a potential control method. Although Poterioochromonas can live and retain its grazing ability even at the low pH of 3.5, it is more sensitive to alkaline environments (Ma et al 2022a). Touloupakis et al (2016) found that contamination with Poterioochromonas was eliminated in Synechocystis cultures grown in a medium with a high pH (above 11.0); however, the microalgal productivity at pH 11.0 decreased by 32% compared to that at pH 7.5.…”

“…However, the biomass of Poterioochromonas in these studies was insufficient to evaluate the viability and controlling effect on Microcystis blooms of Poterioochromonas in the field. Taking advantage of the high biomass derived from heterotrophic fermentation, our group found that chemoheterotrophic P. malhamensis can live in the aquatic environment of a Microcystis bloom and promote the sedimentation of colonial Microcystis cells (Ma et al 2022a).…”

“…To eliminate the harmfulness of Poterioochromonas on microalgal growth, a diverse range of methods for early detection and prevention as well as control have been successively established. On the other hand, the benefits of Poterioochromonas, such as its grazing on the harmful genus Microcystis (Ma et al 2022a) and its application in the bio-manufacturing of bioactive molecules (Ma et al 2021), have been well explored. Moreover, with the breakthrough of high-cell-density cultivation, the resource utilization of Poterioochromonas has attracted quite a lot of attention.…”