TECHNOLOGY FOCUS - BIOLOGY - Preferred Composition: The reaction solution contains fermentation organism and/or cellulase enzyme.    TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Process: The reaction solution is separated into ethanol and non-fermented solids by beer column tray separation, paddle dryer apparatus separation, twin screw conveyor separation, rotary valve separation, butterfly valve separation, distillation and/or centrifuging. The activated carbon is added to biomass substrate or liquid reservoir.    TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Component: The flow-through reactor has a reactor vessel with a perforated screen (i) and a perforated screen (ii), the biomass is suspended between the perforated screen (i) and perforated screen (ii), the reactor vessel has a fluid inlet and a fluid outlet, and a fluid passageway. An end of the fluid passageway is connected to the fluid inlet, and the other end is connected to the fluid outlet of the reactor vessel. The flow-through reactor further has a pump to facilitate recirculating liquids. The pump is disposed in the fluid passageway between fluid inlet and fluid outlet. Preferred Process: The recirculation of solution is driven by build-up of fermentation gas in the flow-through reactor.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The lignocellulosic biomass is pre-treated, before suspending in the reactor. The migration of reaction solution is driven by gravity or pressure. The portion of carbohydrates in the lignocellulosic biomass is biologically converted by hydrolyzing cellulose and/or hemicellulose to obtain oligosaccharide and/or monomeric sugar and/or fermenting oligosaccharide and/or monomeric sugar to obtain ethanol. The reaction solution in the liquid reservoir is removed, and the solution is processed to separate ethanol and non-fermented solids in the reaction solution. The biomass substrate is partially submerged in the reaction solution in the liquid reservoir. The ethanol is produced by suspending pretreated lignocellulosic biomass in flow-through reactor, hydrolyzing biomass to obtain monomeric sugars, supplying reaction solution through the biomass, recirculating reaction solution and fermenting monomeric sugars. The hydroxylation is carried out by chemically hydrolyzing cellulose and hemicellulose to obtain monomeric sugars. The hydrolyzing process and fermentation process are carried out concurrently, and in presence of activated carbon.