Ozone pretreatment of humid wheat straw for biofuel production

Abstract

In an attempt to maximize the amount of ozone reacting with lignin inside humid wheat straw, some of the ozone-reactive lignin degradation products were washed away before a second ozonolysis delignification stage. The total contact time for the two stages was kept the same as that for a one-stage process for comparison. A significant decrease in the Acid Insoluble Lignin (AIL) content of the straw resulted: from 13.04 wt. % (after a 30-min one-stage ozonolysis) to 9.34 wt. % (after a 30-min two-stage ozonolysis, separated by a washing step). This significant improvement was accompanied by an increase in released fermentable sugars from an enzymatic hydrolysis. The yield increased from 60% theoretical sugars to 80%. A further improvement in AIL (down to 7.36 wt. %) and released sugars (up to 90% theoretical) occurred when the moisture content (MC) of the straw entering the second stage was adjusted to the optimum value of the straw entering first stage (45 wt. %, predicted from an experimental design). The authors believe this is the first time results are published for the introduction of a two-stage process separated by a washing step. 542

A review on extraction, chemical treatment, characterization of natural fibers and its composites for potential applications

“…The fiber morphology was altered by increasing the degree of crystallinity and crystallites size. [206][207][208] The ozone treated soybean fiber has potential improvement with whiteness and the effect on a substrate is less. The increase in ozone treatment duration results in a decrease in the burst strength of soybean composites.…”

Lignocellulosic Biomass Transformations via Greener Oxidative Pretreatment Processes: Access to Energy and Value-Added Chemicals

“…The high oxidative power for decomposing the lignin component, the ease of onsite generation and utilization of ozone, and the non-inhibitory reaction products of ozonolysis, are some of the major reasons that render this greener oxidant as an attractive biomass pretreatment alternative. Ozonolysis of various biomass has been reported in the past decades, that includes cereal straws (Al jibouri et al, 2015 ; Garcia-Cubero et al, 2016 ), wood and sawdust (Mamleeva et al, 2009 ), sugarcane bagasse (Barrerra-Martinez et al, 2016 ), grass, and cotton stalks (Kaur et al, 2012 ; Travaini et al, 2016 ); the comprehensive progress made on ozonolysis of lignocellulosic biomass has been reviewed recently (Travaini et al, 2016 ).…”

“…Alternatively, process design can improve the effectiveness of ozonolysis for energy conversion as exemplified by Al jibouri et al ( 2015 ) in a two-step process for pretreatment of humid wheat straw; an intermediate washing procedure was sandwiched between two ozonation processes which was critical to re-exposing lignin functional groups by washing away organic acid molecules generated from the initial ozonation period, thus sustaining the effectiveness of the process. Under an optimized condition with initial MC of 45%, ozone concentration of 3% wt., washing start time of 20 min after initial ozonation and washing time of 80 s, the fermentable sugar yield by the ensuing hydrolysis process improved by 30% as compared to a one-step ozonolysis without intermediate washing, and 4 times better than untreated wheat straw.…”

Gradual Accumulation of Heavy Metals in an Industrial Wheat Crop from Uranium Mine Soil and the Potential Use of the Herbage

“…Determined on the basis of randomly drawn 100-plant sets, the number and FW of grains from soil-A grown plants reached 47.7% and 39.5%, respectively, of the values for soil C-grown plants. The 1000-seed FWs from both locations differed significantly by 12% ( Table 2).…”