Author(s): Rodríguez-Hernández JL, goncalves A, Moraes- Rochag, Nevárez gV, Peralta MR, Muñoz-Castellanos L, Arevalo S, Ayalag, Carrillo- Campos J and Ballinas-Casarrubiasm L
Chihuahua desert possesses 60% of the Opuntia species (nopal) naturally grown in Mexico. These species are considered a reserve material due to its tolerance to adverse weather conditions, and some have been used as cattle forage regardless their low protein content. One of the traditional ways for protein enrichment is through yeast fermentation using S. cerevisae. In the present work, several routes have been assessed to augment cellulose bio availability during fermentation. The protein enrichment process, coupled with an additional thermal, enzymatic or fungal treatment in a semi-solid culture is evaluated. The yeast concentration was the constant parameter in the culture at 15% wet basis. Six different treatments were proposed considering :a. Thermal treatment; b. Fermentation using Phanerochaete chrysosporium A594; c. Novozyme 188 and Celluloclast thydrolysis; d. Fermentation with S. cerevisiae at 37° C for 48 h, 180 rpm. For each sample, lignin, cellulose and protein were measured. The results are as follows. Protein at original sample was of 0.042%, and its content (%) in the different treatment combinations was: a and d: 16.5; a,b and d:22.8; a,c and d:10.6; d:14.3; b and d: 25.9, c and d:8.75. Therefore, thermal processing did not contribute to the increase in protein content in the final product, neither was the enzymatic pre-treatment. Fungal solid state fermentation contributed significantly to the increment in protein content due, principally, to the lignin depletion in the fermentation media.
