OZONE PRETREATMENT OF LIGNOCELLULOSIC MATERIALS: THE EFFECT OF OZONE CONSUMPTION ON REACTIVITY IN ENZYMATIC HYDROLYSIS INTO SUGAR

Abstract

Ozonolysis, as a lignocellulosic biomass pretreatment for sugars and bioethanol production is becoming widespread in recent years owing to its efficiency and environmental safety. Ozone reacts preferably with lignin than carbohydrates, leading to biomass delignification, and so the sugar release by enzymatic hydrolysis. Sugars yield depends on ozone pretreatment parameters and additional studies are necessary to optimize the process to achieve high yields with economic feasibility.
 In this work some general patterns of ozone pretreatment are established, using the samples of plant biomass of various types (straw, soft and hardwood). It is shown that the reactivity of vegetable substrates pretreated with ozone is determined by the amount of ozone consumed and practically does not depend on the conditions under which this value of ozone consumption was achieved. The optimal value of ozone consumption, which allows to obtain the maximum yield of sugars in the enzymatic reaction, is 2–3 eq. O3/C9PPU (in terms of phenyl-propane structural unit of lignin, contained in the raw material) or 10–15 wt.%. Intermediate ozonation products do not exhibit inhibitory properties at such ozone consumption.