Study of sulphuric acid catalysed steam pretreatment of the hardwood anadenanthera colubrina

Resumo

Hemicellulose from lignocellulosic materials constitutes a large potential source of fermentable sugars to be used for fuel production. The hardwood Anadenanthera colubrina is used in the South American forest industry. The wood (and its residues) has a high carbohydrate content (cellulose 43% and hemicellulose 21%) and may be of interest as a lignocellulose feedstock for fuel production. The aim of the present study was to determine conditions for a good recovery of hemicellulose, primarily pentose sugars from that material. A. colubrina hardwood was subjected to steam pretreatment using dilute sulphuric acid (H₂SO₄ = 0.5 or 1.5 % (w/w)), at a temperature between 180 to 220 °C, a holding time of 300 or 600 s and two moisture contents (40 – 60%). Acid hydrolysis gave a good recovery of pentose sugars, with a xylose yield of 68%, and only minor amounts of degradation products in terms of furan compounds. Only minor proportion of the lignin was solubilised. Acid catalysed steam pretreatment thus appears to be a suitable pretreatment process for extraction of hemicellulose sugars from this feedstock to be used in fermentation processes.

Keywords:

Anadenanthera Colubrina; Ethanol; Steam Pretreatment