Vitae (Feb 2009)
SELECTIVE DELIGNIFICATION OF THE <I>Pennisetum purpureum x Pennisetum typhoides</I> GRASS USING LIGNINOLYTIC BASIDIOMYCETES
Abstract
Samples of Pennisetum purpureum x Pennisetum typhoides grass of 120 days are put under selective fermentation in solid state with two strains of basidiomycetes fungi Ganoderma ssp and Lentinus ssp, during seven weeks. The delignification characterization is made by Fourier Transform Infrared Spectroscopy (FTIR) measuring the areas of the main characteristic bands. In the samples treated with the Ganoderma ssp strain, a loss of 70% of aromatic compounds in relation to the aliphatics is obtained (by FTIR); also are obtained in the zero and seventh weeks, the acid-detergent lignin (ADL) (55,9% and 10,7%, respectively) as well as the contents of dry matter and cellulose that vary from the 73,3% to the 92,9% and from the 3,1% to the 51,7% respectively between the zero and seventh weeks, results that confirm an selective degradation of the lignin. The digestibility tests in vitro, that are in according with the in situ test, do not evidence an improvement in the grass digestibility by the ruminants. As this is degraded by the Ganoderma ssp strain is not obtained an increase of the digestibility of the dry matter, corroborating the ideas explained for other authors who affirm that the ingestion of fungi can be toxic for the rumen’s microflora, and therefore to be toxic for the animals also.
