Utilization of sugar cane bagasse hemicellulosic hydrolyzate by Candida guilliermondii for xylitol production

Effect of pH and activated charcoal adsorption on hemicellulosic hydrolysate detoxification for xylitol production

“…4 -8 To reduce the concentrations of these compounds, eliminating or decreasing their inhibitory effects, various biological, physical and chemical detoxification methods have been proposed. Among the chemical methods, two stand out as being inexpensive and producing good results: pH adjustment to induce precipitation and/or instability of the toxic compounds, 4,9 and the adsorption of these compounds on activated charcoal. 5,8,10 Combinations of these treatments have been used widely for the detoxification of lignocellulosic hydrolysates.…”

Adaptation and reutilization ofCandida guilliermondii cells for xylitol production in bagasse hydrolysate

“…The species Candida sp. (GONG et al 1981), Candida guilliermondii (ROBERTO et al 1991, FELIPE et al 1993 and Debaryomices hansenii (PARAJÓ et al 1996, DOMINGUES et al 1996 can be employed in the production of xylitol from xylose present in hydrolysates derived from agro-industrial lignocellulosic residues. Undoubtedly, sugar cane bagasse constitutes a suitable raw material for xylitol production, because its hemicellulosic fraction, which is mostly composed of xylose (80%) (KUHAD and SING 1993), is a residue plentifully available in ethanol distilleries.…”

“…At the same time, however, the concentrations of the by-products originally present also increase, leading to the reduction on the xylose-fermenting capability of the yeast (FELIPE et al 1997). Usually, the inhibitors are removed by adsorption on active charcoal or by ionic exchange resin ( VAN ZYL et al 1991, DOMINGUEZ et al 1996 and by alkaline-acid precipitation (ROBERTO et al 1991).…”

Avaliação de diferentes tipos de carvão ativo na destoxificação de hidrolisado de palha de arroz para produção de xilitol

“…Geralmente, os substratos lignocelulósicos necessitam de tratamento prévio para que se tornem mais susceptíveis à ação de microrganismos [21,29]. Vários autores têm utilizado carvão ativo em processos de destoxificação de hidrolisados lignocelulósicos [1,7,18] Na Tabela 3 encontram-se também apresentados os resultados referentes à influência do tratamento na remoção de furfural, HMF e PDL, empregando os diferentes tipos de carvão ativo.…”

“…Para contornar os problemas de toxicidade dos hidrolisados, vários procedimentos têm sido utilizados incluindo a precipitação de impurezas com a variação de pH [21], adsorção em carvão ativo [18], resinas de troca iônica [10], entre outros. Dentre estes procedimentos, destaca-se o uso de carvão ativo, que vem sendo amplamente utilizado em processos de destoxificação para produção de xilitol [1,7,18].…”