NOVELTY - The process for treating a eukaryotic cell-derived biomass-containing stream to produce methanol, ethanol or methane, comprises passing the stream through a chamber, pressurizing the stream, introducing a gas e.g. carbon dioxide into the pressurized stream, where the gas is soluble within the eukaryotic cell-derived biomass, depressurizing the stream to cause the solubilized gas to expand and disrupt the eukaryotic cell-derived biomass, and passing the depressurized stream into an anaerobic or aerobic bioreactor. The eukaryotic cell-derived biomass comprises plant-derived material.    USE - The process is useful for treating a eukaryotic cell-derived biomass-containing stream to produce methanol, ethanol or methane (claimed) or other fermentation products such as lactic acid, butyric acid or acetone.    ADVANTAGE - The process improves the efficiency of bioreactors by releasing compounds such as sugars from the biomass stream.    DETAILED DESCRIPTION - The process for treating a eukaryotic cell-derived biomass-containing stream to produce methanol, ethanol or methane, comprises passing the stream through a chamber, pressurizing the stream, introducing a gas e.g. carbon dioxide into the pressurized stream, where the gas is soluble within the eukaryotic cell-derived biomass, depressurizing the stream to cause the solubilized gas to expand and disrupt the eukaryotic cell-derived biomass, and passing the depressurized stream into an anaerobic or aerobic bioreactor. The eukaryotic cell-derived biomass comprises: plant-derived material; cellulose, lignin and/or hemicellulose; wood drippings, paper, sawdust, herbaceous plant material, grass clippings, algae, mixed food materials, cotton, hemp and/or flax; proteinaceous animal material such as collagen, flesh and/or spinal tissue; municipal waste; and food waste. The process further comprises treating the stream with one or more chemical, physical or biological treatments before and/or during the pressurization step. The chemical treatment comprises treating with a wetting agent, an acid, a base, a surfactant and/or oxidizing agent, and heating the stream with steam. The biological treatment takes place by enzymes and/or micro-organisms. The gas obtained from the bioreactor is collected and introduced into the pressurized stream. The waste material from the bioreactor is dried and burned to directly or indirectly heat the stream. An aqueous liquid is added to the eukaryotic cell-derived biomass prior to passing the stream through the chamber. An INDEPENDENT CLAIM is included for an apparatus for treating a eukaryotic cell-derived biomass-containing stream.    DESCRIPTION OF DRAWING(S) - The diagram shows a flow diagram of a process for treating a eukaryotic cell-derived biomass-containing stream.