CCALA Culture Collection
of Autotrophic Organisms

Handling of Received Cultures

Critical Points

The culture may be stressed after transport. Handle it gently and avoid sudden changes in temperature, light intensity or medium composition.

• Unpack and inspect the culture immediately.

• Avoid direct sunlight, overheating, freezing and sudden light or temperature changes.

• Allow the culture to acclimatise before intensive manipulation.

• Work aseptically and use fresh sterile medium.

• Do not over-dilute weak cultures during the first transfer.

• Keep the original culture as a backup until new growth is confirmed.

Upon Arrival

• Unpack the culture immediately after delivery. Check the tube or flask for leakage, breakage, drying of agar, unusual colour, turbidity or visible contamination. If the culture appears damaged or in poor condition, document it with photographs before further manipulation.

• Inspect the culture before transfer. Whenever possible, check the culture microscopically to assess cell condition, density and possible contamination. Do not rely only on the colour of the culture, as some strains grow at very low cell densities.

Initial Acclimatisation

• Allow the culture to acclimatise gradually. Place it under the recommended cultivation conditions, preferably under low to moderate light at first. Avoid direct sunlight, overheating, freezing, prolonged darkness and abrupt temperature changes.

• Do not refrigerate the culture unless specifically recommended. Some strains tolerate low temperatures, but others may be damaged by cold storage. Keep the vessel closed, but avoid excessive tightening if gas exchange is required. Do not open the culture unnecessarily before transfer.

Aseptic Handling

• Use aseptic technique for all manipulations. Work in a laminar flow cabinet whenever possible. Use sterile media, sterile vessels and sterile pipettes or inoculation loops. Minimise the time the culture vessel remains open.

Transfer into Fresh Medium

• Subculture the strain into fresh sterile medium after initial acclimatisation. In most cases, transfer should be performed within a few days after receipt. If the culture appears strongly stressed, it may be preferable to let it recover for 1–2 days under suitable conditions before subculturing. 
• Do not dilute weak or stressed cultures too much during the first transfer. For routine transfer into liquid medium, inoculate a portion of the received culture into fresh sterile medium. A moderate dilution, for example approximately 1:2 to 1:5, is usually safer for the first recovery transfer than a very high dilution. Dense and healthy cultures may be diluted more.
• Keep part of the original received culture as a backup. Do not discard the original tube or flask immediately after transfer. Keep it under suitable conditions until active growth is clearly visible in the new culture.

Culture Subculturing and Transfer

Transfer from Liquid Culture to Liquid Medium

1. Gently homogenize the liquid culture if appropriate. Avoid vigorous shaking, foaming, or excessive disturbance of the culture.

2. Using a sterile pipette, transfer an appropriate volume of the liquid culture into fresh sterile liquid medium in a sterile tube or flask.

3. Close the tube or flask properly and incubate under the recommended light, temperature, and other strain-specific conditions.

Transfer from Agar to Liquid Medium

1. Using a sterile loop, gently collect a small amount of culture from the agar surface. Avoid excessive scraping or damaging of the agar surface.

2. Transfer the culture into fresh sterile liquid medium in a sterile tube or flask.

3. Close the tube or flask properly and incubate under the recommended light, temperature, and other strain-specific conditions.

Transfer onto Agar Medium

1. Using a sterile loop or sterile pipette, collect a small amount of culture from the source culture.

2. Gently streak or spread the culture over the surface of fresh sterile agar medium.

3. Avoid breaking, tearing, or excessively disturbing the agar surface.

4. Close or seal the agar slant appropriately and incubate under the recommended light, temperature, and other strain-specific conditions.

Follow-up Monitoring

• Monitor the culture regularly after transfer. Check for recovery, growth, colour change, clumping, contamination or drying of agar. Some strains resume growth within a few days, while slow-growing or transport-stressed strains may require several weeks.

• Follow strain-specific instructions whenever available. Optimal medium, temperature, light intensity, salinity, transfer interval and growth rate can differ substantially among algal and cyanobacterial strains.