THE DESCRIBED METHOD SUBJECT FOR PATENCY INVOLVES CULTIVATION SYSTEM FOR MUSHROOMS IN VESSELS OF DIFFERENT VOLUME UNDER STERILE CONDITIONS. THE VESSELS ARE USED AS LOW COST BIOREACTOR. THE PROPOSED BIOREACTOR COMPOSED OF STERILIZABLE VESSEL OF TOTAL VOLUME RANGED FROM 1-40 LITER INCLUDING A LID WITH 4 PORTS. ( 2 GAS INLET AND TWO GAS OUTLET). EACH PORT IS CONNECTED TO HYDROPHOBIC STERILIZABLE GAS FILTER OF 0.22 MICRON. THE INLET PORTS ARE CONNECTED WITH TUBES MADE OF SILICON OR STERILIZABLE PLASTIC INSIDE THE VESSEL . THESE TUBES WERE PERFORATED EITHER REGULARLY OR IRREGULARLY. THIS TO MAKE THE AIR BUBBLES IN SPECIFIC SIZE OPTIMUM FOR BOTH AERATION AND MIXING AT THE SAME TIME