Abstract: An apparatus for bioconversion of vegetal raw material comprises a bioreactor communicable with a means for charging this material and discharging the end product. A pressure-sealed chamber for storing excess liquid displaceable from the bioreactor is provided with a liquid level control means and connected to a source of compressed air, atmosphere, inoculator, steam source and bioreactor. A distributor of gas-steam, gas-liquid flows and a flow of inoculum is connected to the liquid level control means and inoculator. Feeders are disposed inside the bioreactor at various levels in terms of height thereof and connected to the flow distributor, a pump being provided between the bioreactor and steam source. A control unit is electrically connected with the bioreactor, steam source, inoculator, compressed air source, a pressure-sealed chamber, flow distributor, and pump.