HidrÃlise e oxidaÃÃo catalÃtica dos carboidratos do bagaÃo de cana-de-aÃÃcar em operaÃÃes descontÃnuas

AUTOR(ES)

Isaias Barbosa Soares

DATA DE PUBLICAÇÃO

2008

RESUMO

In the local context, is clearly meet the need to enhance the sugarcane bagasse as biomass plant. Sugar cane bagasse is a waste coming from alcohol and sugar industries and available abundantly. This availability of sugarcane bagasse as raw material at low cost, combined with the feasibility of its recovery via chemical and biochemical processes, is the foundation of technical and scientific initiatives that could make real the production of chemicals with high-value (polyols, organic acids) from carbohydrates of cellulose and hemicellulose. Currents prospects show slurry bed reactors as potentially suitable for processing such raw material, by catalytic oxidation of its components (carbohydrates). In this paper, it was developed catalytic oxidation studies of glucose coming from sugarcane bagasse, intending its chemical valuation. Thus, it was used steam pretreated sugarcane bagasse as feedstock. First, it was proceeded an enzymatic hydrolysis of it, previously subjected to three conditions: pretreated bagasse natural (not washed), bagasse washed with distillated water and bagasse washed with 1% NaOH solution. In each of these conditions it was also varied the size of the pretreated bagasse (natural size and 20 mesh size) and proportion of enzymes used on hydrolysis (23.4% of cellobiohydrolases/endoglucanases blend-5.3% of β-Glucosidase; 23.4% of cellobiohydrolases/endoglucanases blend-0% of β- Glucosidase and 11.7% of cellobiohydrolases/endoglucanases blend-5.3% of β-Glucosidase) in relation to mass of pretreated sugarcane bagasse used. A pure glucose solution was catalytically oxidized with O2, using Pd on alumina supports on batch glass reactor. Similarly, it was tried to oxidize, in the same reactor, a hydrolysate mixture of hydrolysates obtained in the step of enzymatic hydrolysis of pretreated bagasse. Pretreated sugarcane bagasse washed with 1% NaOH solution, without milling shows best glycoside yields within 3 proportions of enzyme used reaching values of 0.35g, 0.42g and 0.41g of glucose per gram of pretreated sugarcane bagasse. Pure glucose solution oxidation reached maximum conversion of 41%, with maximum selectivity less than 50% to gluconic acid. Batch glass reactor showed be not suitable for oxidation of enzymatic hydrolysate

ASSUNTO(S)

hidrÃlise enzimas glicose hydrolysis enzyme glucose sugarcane bagasse bagaÃo catalytic oxidation engenharia quimica oxidaÃÃo catalitica

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