The microbial protein bioconversion of cactus pear by yeast in solid medium was studied. Three cultivation variables used were: inoculum's concentrations (5, 10 and 15 %), substrate layer thickness (2, 4 and 6 cm) and temperature (30, 34 and 38 ºC). The rate of dry matter production and total protein were determined. Results obtained were variance analysis, gross energy and in vitro dry matter digestibility. The maximum protein amount achieved for the conditions studied in the present work was higher than 26 %, which was compatible or greater than those of conventional concentrates of protein supplements used for animal feed. The protein concentrate of cactus pear had a higher in vitro digestibility index (95.8 %) and did not show any changes in the gross energy value when compared to that of the cactus pear in natura.
Protein enrichment; solid-state fermentation; cactus pear; yeast
