The microalgae culture collection of Taras Shevchenko National University of Kyiv (acronym ACKU - Algae Culture Collection of Kyiv University) is registered with the World Federation for Culture Collections, registration number WDCM994.

Initially, the collection was based on strains isolated from Ukrainian soils. Later the collection was supplemented by strains isolated from terrestrial habitats of Antarctica, as well as by significant number of strains (mostly authentic) from two leading world culture collections of microalgae: SAG (Germany) and CCAP (UK). The ACKU collection's special value lies in the fact that it contains many strains of microalgae isolated from biotopes that have been destroyed due to the active phase of the Russian-Ukrainian war or are located in territories temporarily occupied by Russia (such as Crimea, Donetsk, Luhansk, Kherson, Zaporizhzhia regions, and Snake Island). This makes the ACKU collection a biodiversity conservation center for war-torn areas.

A brief history of the ACKU creation

In the early 70s of the twentieth century, Professor of the Lower Plants Department, DSc N.P. Masyuk created an original collection of strains of species of the genus Dunaliella Teod., isolated from different regions of the former USSR in the process of revision of this genus (Masyuk, 1973). This was the first step in the establishment of a collection of microalgae cultures at the Taras Shevchenko Kyiv State University (now Taras Shevchenko National University of Kyiv). All strains from N.P. Masyuk personal collection were subcultures of the original strains, which are currently stored in the Collection of microalgae cultures of M.G. Kholodny Institute of Botany of National Academy of Sciences of Ukraine (Kyiv) (acronym IBASU-A), and form the basis of the latter.

In the 80s of the 20th century, the collection of cultures of the Department of Lower Plants was replenished with more than 250 strains of 170 species of microalgae, isolated by I.Y. Kostikov from the soils of the Forest-Steppe zone of Ukraine and the Ukrainian Carpathians. Unfortunately, in 1988, when the Faculty of Biology of KNU moved to a new building, unqualified transportation and temporary placement of the collection in an unsuitable room led to the loss of almost all strains of the collection of the Department of Lower Plants, including unique authentic strains of new taxa (Polytomella zerovii Massjuk et Kostikov, Polytoma kievense Kostikov, Spongiochloris irregularis Kostikov, Nautococcus verrucosus Kostikov, Hyalogonium massjukiae Kostikov) and unique isolates of species that are absent in other collections (in particular, Schizogonium murale Kuetz., Capitulariella cf. radians Pasch.).

The restoration of the microalgae collection of Kyiv University began in 1990-2000 during large-scale floristic studies of soil algae in Ukraine (Kostikov et al., 2001), Belgium and Luxembourg (Kostikov et al., 2001; Hoffmann, Ector, Kostikov, 2007), as well as some reserves of russia (Daursky, Lazovsky, Ussuriysky). As a result, several personal collections were created at the Department of Botany – I.Y. Kostikov, E.M. Demchenko, T.M. Darienko, P.O. Romanenko, A.A. Kryvenda, N.A. Rybalka, S.O. Yarovyi, as well as a number of strains of the collection of soil algae of the Department of Lower Plants were restored from dehydrated cultures (Demchenko, 2000).

In 2002, the new and most taxonomically interesting strains from these personal collections, together with a set of strains from Dr. A. Lukeshova (Institute of Soil Biology, Česká Budojovice, Czech Republic), transferred to the Department of Botany for revision of the family Radiococcaceae (Kostikov & al., 2002), were consolidated in ACKU (Kostikov, Novokhatska, 2003).

Since 2002, the ACKU has been enriched with strains isolated from terrestrial habitats of Antarctica (Kostikov & al. 2003) and various inland waters of Ukraine, as well as a significant number of strains (mostly authentic) from two of the world's leading collections of microalgal cultures: SAG (Sammlung von Algenkulturen at Universitat Gottingen) of the University of Gottingen (Germany) and CCAP (Culture Collection of Algae and Protozoa), the national collection of algae and protozoa cultures of the United Kingdom. In 2009. ACKU publishes the first catalog of strains (Kostikov, Demchenko, Novohatska, 2009).
At the beginning of 2020, the ACKU collection numbered 1,079 strains, of which 246 strains were authentic.

Main characteristics of the collection

Unfortunately, the start of the large-scale phase of russian aggression against Ukraine caused serious damage to the collection. For almost a year, ACKU endured unstable lighting and temperature fluctuations, and on December 31, 2022, the building that hosts the main collection was partially damaged by a missile strike.

After thoroughly revising* the ACKU collection from 2023 to 2025, it was determined that the collection currently contains 235 algal strains representing 85 genera from the divisions Chlorophyta, Heterokontophyta, Charophyta, and Cyanobacteria.

Of the 235 strains, 31 are authentic taxa, including Interfilum terricola (J.B.Petersen) Mikhailyuk et al. (ACKU 57-02), Elliptochloris perforata Hoffmann & Kostikov (ACKU 75-02), Chlamydomonas ucrainica Demchenko, Massalski, Kostikov & Hoffmann (ACKU 125-02), Garhundacystis spadensis I.Kostikov & L.Hoffmann (ACKU 190-03), Chlorochytrium hypanicus I.Y.Kostikov, E.N.Demchenko, V.R.Boiko & A.A.Gontcharov (ACKU 222-02), Pleurastrosarcina brevispinosa var. borysthenica Petlovana, Darienko & Pröschold (ACKU 382-04), and others.

Today, ACKU continues its work to preserve microalgae strains, which are a valuable resource for the scientific community. Despite the difficult circumstances, the collection will continue to grow.

The collection is stored in an equipped room, with periodic (16 hours - light phase / 8 - dark) artificial lighting with a controlled temperature regime (11-20°C). All strains are algologically pure, not axenic. Strains are stored mainly in test tubes on solid agar nutrient media BBM, 3NBBM, BBM-V, K, SA (97% of strains). Each strain is represented by subcultures of three lines of reseeding (line 1 - age up to 3-12 months, line 2 - from 3-12 months to 1.5-2 years; line 3 - from 1.5-2 years to 3-3.5 years). About 3% of the strains are stored on liquid nutrient media BBM, 3NBBM and K in flasks with a volume of 100-250 ml, and are also represented by three lines of subcultures similar to cultures on agar medium. The purity of strains is controlled when carrying out reseeding on fresh nutrient media, as well as selectively - when conducting research work with specific strains and when issuing strains at the request of various organizations and individual scientists. All strains are documented by micrographs and have universal passports. For some strains (about 250), blocks poured into Spurr resin for transmission electron microscopy were made in parallel with live cultures. About 200 strains were characterized using DNA barcoding technologies based on nuclear nucleotide sequences of the ribosomal gene cluster (18SrDNA, ITS-2) and chloroplast sequences of the rbcL gene and the rbcL-psbA spacer.

On the basis of the ACKU microalgae collection, various research and educational works have been carried out and are being carried out. Research developments mainly concern the following areas:

• classical and molecular taxonomy of microalgae,
• flora of terrestrial algae of Ukraine and the Ukrainian sector of international responsibility in the Antarctic (area of the Ukrainian Antarctic station «Akademik V.I. Vernadsky», archipelago of the Argentine Islands),
• physiology of algae,
• phycotechnology (development of technologies for obtaining algal biomass and algal raw materials of various compositions, development of filtration technologies industrial smoke and gas emissions),
• algae ecology.

Scientific achievements:

1. The role of terrestrial eukaryotic algae as one of the reservoirs of viral infections of higher plants has been determined (Boyko et al., 2004).
2. The regularities of the influence of microwave irradiation on microalgae are indicated (M.A. Berezovskaya).
3. The role of microalgae in the formation of therapeutic silt sulfide peloids has been established (S.O. Yarovyi, A.M. Solonenko).
4. The molecular phylogenetic concept of the species in microalgae has been clarified (Rybalka et al., 2009).
5. New producers of technologically valuable substances, in particular, astaxanthin have been proposed (E. Chelibeeva)
6. The problem of taxonomy of a number of critical groups of microalgae has been solved, in particular, the order Protosiphonales (Kostikov et al., 2012), the family Radiococcaceae (Hoffmann, Gugger, Kostikov, 2002; Kostikov, Darienko, Lukešová, Hoffmann, 2002), genera Pseudococcomyxa (Kostikov, Darienko, Hoffmann, 2002), Stichococcus (Karbovskaya, Kostikov, 2012), Interfilum (Mikhailyuk & al., 2008), Chlamydomonas (Pavlovska, Kostikov, 2011; 2012).
7. A number of new for science taxa have been described, in particular, a new genus Garhundacystis (Kostikov, Hoffmann, 2000), many new to science species (Kostikov, Hoffmann, 2002; Demchenko & al., 2003; Hoffmann, Ector, Kostikov, 2007; Mikhailyuk & al., 2008; Kostikov et al., 2012, Petlovana, Darienko, Pröschold, 2025). The results of the research have been published in numerous articles (including more than 20 articles in international professional journals with an impact factor) and one monograph (Kostikov et al., 2001).

Educational value:

• The workshop for identification of terrestrial algae during the First International Conference International Conference «Algae in terrestrial ecosystems» (Kaniv, September 27-30, 2005). The participants of the school were 60 scientists from 12 countries (Kondratyuk et al., 2005).
• International specialized training in identification of soil and aerophytic eukaryotic algae using ACKU collection reference strains. (Kostikov et al., 2010).
• The strains from the ACKU are regularly used in the laboratory practice of the normative courses «Botany», «Plant Biology» and «Soil Science and Soil Microbiology» for bachelor students of the ESC «Institute of Biology and Medicine» of Taras Shevchenko National Universityof Kyiv.
• The strains from the ACKU are regularly used in the laboratory practice of the special courses «Algology», «Molecular Taxonomy of Plants», «Phycotechnology and Industrial Cultivation of Fungi».
• Providing materials for students to use in researching their Bachelor's and Master's theses.
• Providing material for the practical round of the IV (All-Ukrainian) stage of the School Olympiad in Biology (2005-2010) and during the training camp of the national team of Ukraine for the International Student Olympiad in Biology (2007-2011).
• Providing strains of secondary schools of Ukraine for practical classes, ensuring the work of school biolog clubs, performing research work of schoolchildren submitted to the competition of the Junior Academy of Sciences (JAS).
• Providing materials for Summer Biology School for Gifted Students (2018-2019).
• Providing materials for educational project «BioSchool» (2024).

*This work has received funding through the EURIZON project, grant agreement No.871072.