Complex sentence: As the microoganisms degrade the biomass and convert it into a mixture of carboxylic acids, the pH must be controlled, which is done by the addition of a buffer (e.g., ammonium bicarbonate, calcium carbonate), thus yielding a mixture of carboxylate salts.
Split into simpler sentences: As the microoganisms degrade the biomass and convert it into a mixture of carboxylic acids, the pH must be controlled. This is done by the addition of a buffer (e.g., ammonium bicarbonate, calcium carbonate), thus yielding a mixture of carboxylate salts.