SacO2 is known for its heat resistant, breathable bags, with a series of parallel filter seams. These bags are successfully used by spawn producers and substrate producers who sterilise individually portioned nutrient mediums. The raw material used to produce this range of Microsacs is polypropylene, which makes the bags less suitable for bulk production of mycelium. In this case, the bags are irradiated before they are filled with sterilised and incubated substrate, and these this treatment makes the PP bags brittle.

SacO2 has recently extended its equipment by adding a machine that makes polyethylene (PE) and HDPE bags. Production is equally as flexible as the existing PP range, as here too the number and width of the filters, the distance between the filter seams and the type of filter material used can be changed. By varying these elements, the gas exchange capacity can be adapted to suit the product to be incubated, without the risk of dehydration and infection by foreign micro-organisms.

In the new range of bags, the filters are also made up of parallel seams of filter material, attached to the perforated zones in the PE film. The principle of the bags is surface filtration, whereas the PP bags using the principle of depth filtration. Depending on the demands of the product, the filters are made of Tyvec or non woven PE. A Microsac, featuring filters with an extra large gas exchange capacity, has been especially developed for the production of CAC-ing spawn.