the disclosure includes a method , process and apparatus for the conversion of biomass to carboxylic acids and / or primary alcohols . the system may include a pretreatment / fermentation subsystem operable to produce a fermentation broth containing carboxylic acid salts from biomass , such as lignocellulosic biomass . the system may also include a dewatering subsystem operable to remove excess water from the fermentation broth to produce a concentrated product . the system may also includes an acid springing subsystem operable to produce a mixed carboxylic acid product . the system may also include a hydrogenation subsystem operable to produce an alcohol mixture , such as a mixture containing primary alcohols . methods of operating this system or other systems to obtain a carboxylic acid or alcohol mixture are also provided .