Description
Agro-industrial residues are lignocellulosic materials with a high content of cellulose,
hemicellulose and lignin. If such residues can be produced in bioprocesses (e.g. xylanase
production) there is an attractive possibility of their integral use in biotechnological
processes. In general, xylanase biosynthesis is induced by its substrate – xylan, but the high
xylan content of some wastes such as corn cobs and wheat bran makes them an accessible
and cheap source of inducers. Another alternative to improve the xylanase production, which
is the main goal of this work, is the treatment of lignocellulosic materials in autohydrolysis
processes which, under optimized conditions, lead to the solubilization of hemicelluloses
(liquid phase, liquor) that may be favorable to xylanase production. The inclusion of these
components in the nutrient medium composition can be a strategy to optimize the microbial
xylanase biosynthesis. The best conditions for xylanase production were observed when the
microorganism was cultivated in birchwood xylan for 6 days; however, satisfactory results
were obtained using a combination of 1% wheat bran with 2% or 10% autohydrolysis liquor,
for 5 days fermentation, once the xylanase production was around 86-87% of production with
xylan. Besides, the obtained production with 100% wheat straw autohydrolysis liquor was
also interesting, once after 7 days of cultivation, the xylanase production was higher than the
ones obtained with wheat bran or by the combination of wheat bran and liquor.
; Polizeli, Maria de Lourdes T. M. 
