TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred process: In the process above, the first pretreatment protocol or second pretreatment protocol comprises ball-milling, two-roll milling, hammer milling, colloid milling, high pressure, steaming, high energy, radiation, pyrolysis, sodium hydroxide, calcium hydroxide, ammonia, sulfuric acid, hydrochloric acid, hydrofluoric acid, chlorine dioxide, nitrogen dioxide, sulfur dioxide, hydrogen peroxide, ozone, cellulose solvents, ethanol-water extraction, benzene-ethanol extraction, steam explosion, Ammonia Fiber Explosion (AFEX), recombinant microorganisms, or their combination. The solids fraction comprises cellulosic materials or comprises mainly hemicellulosic materials in solution. The liquids fraction comprises mainly hemicellulosic materials in solution, the hemicellulosic materials are hemicellulose sugars, and the liquids fraction further comprises residual chemicals applied in the first pretreatment protocol, their by-products or degradation products, or their combinations, where the residual chemicals are acid. The degradation products are selected from fermentation inhibitors, acids, furfural, hydroxymethylfurfural, phenols, formic acid, and acetic acid. The hemicellulose sugars are glucose, galactose, mannose, xylose, arabinose, or their combinations. Separation is conducted at the same temperature as the first pretreatment protocol. The process further comprising cooling the heated second product mixture, where the second pretreatment protocol comprises heating to a temperature. The process further comprises subjecting the second product mixture to biological conversion or chemical conversion. The process further comprises cooling the heated second product mixture, processing the second product mixture using enzymatic hydrolysis, and subjecting the second product mixture to biological conversion or chemical conversion. The biological conversion comprises enzymatic hydrolysis. The biological conversion is fermentation to afford ethanol. The conversion produces levulinic acid. The process is a batch process or a continuous process. EXAMPLE - No suitable example given.