Characterization of an anaerobic fungus from llama faeces.

An anaerobic fungus was isolated from llama faeces. Based on its morphological characteristics, polyflagellated zoospores, extensive rhizoid system and the formation of monocentric colonies, the fungus is assigned to the genus Neocallimastix. Neocallimastix sp. L2 is able to grow on several poly-, oligo- and monosaccharides. It differs from other Neocallimastix isolates in its inability to ferment inulin. Neocallimastix sp. L2 requires CO2 for growth. In the presence of 100% CO2 in the gas phase glucose is fermented to H2, CO2, formate, acetate, lactate, succinate and ethanol (33.8, 15.4, 74.3, 69.2, 26.7, 8.2, and 28.7 mmol per 100 mmol glucose, respectively). Reduced sulphur compounds can be used as sulphur source and ammonium or amino acids as nitrogen source. The temperature range for glucose fermentation is from 37 to 42 degrees C with an optimum of around 38 degrees C. The pH range for glucose fermentation is from pH 6 to pH 8 with a broad optimum between pH 6.5 and pH 7.5. The zoospores of Neocallimastix sp. L2 contain ribosomal 'globules' and hydrogenosomes. In the kinetosomes of the zoospores spurs, scoops and skirts are visible. In both the rhizoids and the sporangia 'crystal bodies' and hydrogenosomes are present. Mitochondria were not detected in either of these life stages.