Micropropagation Containers

What is the gas exchange capacity of the filters?

Gas exchange capacity depends on the Kv value of the corresponding filter types.


Kv is the volumetric gas exchange coefficient by means of diffusion throughout the filters. It represents the number of gas replacements in the vessels per time unit (unit: GE/day). The Kv is determined by the type of filter, filter length and gas volume in the containers. The measurements were obtained with empty vessels in standard conditions, hence these values are not indicative of the real behavior of a plantlet under specific growing conditions.

Gas exchange is achieved by diffusion throughout a series of depth filters. These conditions ensure optimal functioning:


  • keep the filter zones free of labels or any other objects
  • avoid wetting filters; air dry filters when wet
  • before re-using the lids, clean them with damp cloth (do not soak)
  • choose the suitable filter type (L, XL, XXL, XXL+) with the proper ventilation ratio to achieve an ideal gas  exchange with minimal dehydration

KV value for:

Round Microboxes 0118/80

Oval Microboxes OV80

L: white filter

9,87 GE / day

7,44 GE / day

XL: yellow filter

13,09 GE / day

9,84 GE / day

XXL: red filter

15,58 GE / day

10,83 GE / day

XXL+: green filter

81,35 GE / day

62,87 GE / day

How do I choose the right filter?

Your choice will depend on a number of parameters, such as:


  • plant variety – even different cultivars of the same species may behave differently
  • generation time – i.e. time span needed for growth
  • conditions in the incubation chamber – presence of floor cooling; type of shelves; number and position of the plants on the shelves; air circulation; light regime and intensity; temperature
  • number of plants per container
  • developmental phase of the plants
  • volume and composition of substrate in the culture vessel


As a rule, L, XL and XXL filters are designed for plants with a long gereration time, whereas the XXL+ filters are well suited for plants in need of a high gas exchange and/or plants that spend less time in the Microbox.


Comparative in-situ tests are necessary to decide which filter type is appropriate.

Do I need gamma-irradiated Microboxes or not?



In an autoclave based system, the Microboxes should not be sterilized by means of gamma irradiation.


These boxes are re-usable 7 to 10 times if treated with care.



In a fully automated and sterile system, the Microboxes should be sterilized by means of gamma irradiation.


These boxes are not re-usable. The irradiation and sterile packing take place immediately after the production, prior to shipment.

Tips on autoclaving the Microbox

How do I autoclave the untreated Microbox?

(not gamma-irradiated)

Preferable procedure:


Autoclave containers and medium separately, so PP-containers hold their shape and can be re-used a number of times.


Step 1:

Pack stacked containers and covers separately in an autoclavable bag

Step 2:

Autoclave containers and covers

Step 3:

Unwrap containers and covers in sterile conditions

Step 4:

Fill containers with warm sterilized medium under LAF (Laminar Air Flow)

Step 5:

Carefully snap cover around entire rim to securely close

Step 6:

Store containers with medium in a clean area until time of use

Alternative procedure:


Autoclave containers filled with medium


Step 1:

Fill the containers with medium

Step 2:

Place a piece of non-woven tissue on one edge of each container before closing the lids, to allow vapor to enter the Microbox during autoclaving

Step 3:

If condensation is a problem, cover lids loosely with aluminum foil to prevent filters from getting soaked

Step 4:

Put containers in autoclave

Step 5:

Slowly build up pressure to prevent lids from closing

Step 6:

After sterilization, slowly reduce the pressure in the autoclave. As soon as the containers are removed from the autoclave, remove the non-woven tissue and snap to close each cover completely

Step 7:

Store containers with medium in a clean area until time of use .

Corner of lid left open: no deformation

gas has free passage

quick pressure increase

quick pressure reduction

Hermetically-sealed lid: containers distort with pressure changes

Does the medium in the Microbox dry out when plants stay in the boxes for a long time?

Microbox filters are based on a depth-filtration principle—as opposed to membranes, which are surface filters. Depth filters limit dehydration: the longer the filter plug, the less dehydration. Our white filter strips have the longest filter plugs, the green filters the shortest (thus, the white filter strips limit de-hydration the most). Another factor influencing dehydration is growing medium volume.


Do Microbox-grown plantlets have problems with weaning?

No: thanks to an adequate gas exchange, the plantlets have been well prepared for their autotrophic life during their stay in the vessels, so weaning is no problem.


This innovative filtration technology combined with a polypropylene plastic container results in a new generation of autoclavable plant micropropagation vessels with filter: Barrier against pests and contaminations, high gas exchange, no dehydration and sterile: everything your invitro plants need for healthy development. Located in Belgium, in the centre of Europe, the Microboxes are easily shipped worldwide.

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office address: Veldeken 38 b - 9850 - Nevele - Belgium - phone: +32 9 280 09 80