Prototheca Algae

The achlorophyllous yeast-like microalgae belonging to the genus Prototheca (Trebouxiophyaceae, Chlorophyta) were first described by Kruger in 1894. Basically, the genus Prototheca encompasses six species: P. cutis, P. stagnora, P. ulmea, P. wickerhamii, P. zopfii and P. blaschkeae. (Pore. 1985; Roesler et al. 2006). A seventh species, P. moriformis, is not currently accepted because of its biochemical/genetic resemblance with P. zopfii, (Roesler et al. 2006), which was differentiated into two genotypes: genotype 1 and genotype 2 on the basis of biochemical, serological and 18S-rDNA sequencing data. (Roesler et al. 2006). These microalgae are ubiquitous inhabitants in the environment and contaminants of many substrates. (Nelson et al. 1987). P. zopfii, P. blaschkeae, P. wickerhamii and P. cutis may determine persisting infections in the presence of impaired immunological-cellular systems and/or poor animal care (Lass-Flörl et al. 2007; Jánosi et al. 2001) in both humans and animals.

Our collection encompasses some well characterised field isolates and other strains coming from other cellular banks.

Quality controls

All strains enrolled in our collection are submitted to different cultural and molecular biology control tests in order to evaluate their characteristics, purity and identity.


All isolates were screened for the growth in specific prototheca medium (PIM). Then, a single colony was sub-cultured on Sabouraud Agar and growth at 30°C for 48-72h.


This is performed on all cell cultures prior to freezing and after thawing in order to evaluate the cryopreservation efficiency. Cells were plated on Sabouraud Agar and grown at 30°C for 48-72h.


The identity of each isolate has been confirmed through different molecular biology techniques, such as: direct sequencing of rRNA 18S, species/genotype specific PCR3 and PCR/DNA resolution melting analysis. Ricchi et al. 2011).

Quality management system

IZSLER laboratories, that supply biological resources to IBVR, use testing methods performed according to UNI EN ISO/IEC 17025 quality system.

Updated to July 2022



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