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Microalgae exhibit extensive potential for counteracting imminent challenges in the nutraceutical, pharmaceutical, and biomaterial sectors, but lack economic viability. Biotechnological systems for contamination control could advance the economic viability of microalgal feedstock, but the selection of suitable strains that sustainably promote microalgal productivity remains challenging. In this study, total diversity in phototrophic Chlorella vulgaris cultures was assessed by amplicon sequencing comparing cultures subjected to five different cultivation conditions. Overall, 12 eukaryotic and 53 prokaryotic taxa were identified; Alphaproteobacteria (36.7%) dominated the prokaryotic and C. vulgaris (97.2%) the eukaryotic community. Despite altering cultivation conditions, 2 eukaryotic and 40 prokaryotic taxa remained stably associated with C. vulgaris; diversity between systems did not significantly differ (P > 0.05). Among those, 20 cultivable taxa were isolated and identified by 16S rDNA sequencing. Subsequently, controlled co‐cultures were investigated showing stable associations of C. vulgaris with Sphingopyxis sp. and Pseudomonas sp.. Out‐competition of C. vulgaris due to ammonium or phosphate limitation was not observed, despite significantly elevated growth of Sphingopyxis sp. and Tistrella sp.. (P

Nanosecond pulsed electric field treatment (nsPEF) is a technology-driven, resource-efficient approach fostering microalgae biorefineries for transforming them into economically viable scenarios. A processing window of 100 ns, 7 Hz, and 10 kV cm−1 significantly leveraged phototrophic Chlorella vulgaris and bacterial counts up to + 50.1 ± 12.2% and + 77.0 ± 37.4%, respectively (n = 4; p < 0.05) in non-axenic cultures. Applying the same processing window decreased C. vulgaris (−17.1 ± 13.8%) and prokaryotic (−82.7 ± 14.6%) counts owing to alterations in the prokaryotic community diversity. Principle coordinate analysis of prokaryotic phenotypic fingerprints indicated that phenotype or metabolism related diversity changes in the prokaryotic community affected the treatment outcome. The study fosters the upsurge of industrial-scale nsPEF realization and the economic viability of microalgae biorefineries through improved process understanding and thus control. It perpetuates nsPEF applicability for microalgae feedstock production and several other applications within single-cell biorefineries in the bio-based domain., Bioresource Technology, 319, ISSN:1873-2976, ISSN:0960-8524

Nanosecond pulsed electric field treatment (nsPEF) is an innovative, technology-driven, and resource-efficient approach to foster the upstream performance of microalgae-based biorefinery concepts to transform microalgae into economic more viable raw materials for the biobased industry. A processing window applying three treatments of 100 ns, 5 Hz, and 10 kV cm−1 to industrially relevant phototrophic Chlorella vulgaris in the early exponential growth phase significantly increased biomass yields by up to 17.53 ± 10.46% (p = 3.18 × 10−5). Treatments had limited effects on the carbon and pigment contents, but the protein content was decreased. The longest possible pulse width (100 ns) resulted in the highest biomass yield indicating underlying working mechanisms of enhanced cell proliferation based on intracellular and plasma membrane-related effects. The applicability to eukaryotes and prokaryotes, such as C. vulgaris and cyanobacteria highlights the possible impacts of nsPEF across multiple domains of the biobased industry relying on single-cell-based value-chains., Bioresource Technology, 293, ISSN:1873-2976, ISSN:0960-8524