%0 Journal Article
%T Canola Cake as a Potential Substrate for Proteolytic Enzymes Production by a Selected Strain of Aspergillus oryzae: Selection of Process Conditions and Product Characterization
%A Adriana C. Freitas
%A Ruann J. S. Castro
%A Maria A. Fontenele
%A Antonio S. Egito
%A Cristiane S. Farinas
%A Gustavo A. S. Pinto
%J ISRN Microbiology
%D 2013
%R 10.1155/2013/369082
%X Oil cakes have excellent nutritional value and offer considerable potential for use in biotechnological processes that employ solid-state fermentation (SSF) for the production of high value products. This work evaluates the feasibility of using canola cake as a substrate for protease production by a selected strain of Aspergillus oryzae cultivated under SSF. The influences of the following process parameters were considered: initial substrate moisture content, incubation temperature, inoculum size, and pH of the buffer used for protease extraction and activity analysis. Maximum protease activity was obtained after cultivating Aspergillus oryzae CCBP 001 at 20¡ãC, using an inoculum size of 107£¿spores/g in canola cake medium moistened with 40£¿mL of water to 100£¿g of cake. Cultivation and extraction under selected conditions increased protease activity 5.8-fold, compared to the initial conditions. Zymogram analysis of the enzymatic extract showed that the protease molecular weights varied between 31 and 200£¿kDa. The concentrated protease extract induced clotting of casein in 5£¿min. The results demonstrate the potential application of canola cake for protease production under SSF and contribute to the technological advances needed to increase the efficiency of processes designed to add value to agroindustrial wastes. 1. Introduction Proteases are one of the three largest groups of industrial enzymes and have a wide range of applications in the food, textile, and pharmaceutical industries [1]. Sources of proteases include plants, animals, and microorganisms. However, proteases from plant and animal sources are unable to meet global demand, as a result of which there is a need to develop efficient processes for microbial protease production. In fact, of the hundreds of enzymes currently used industrially, over half are derived from fungi and more than one-third from bacteria, with the remainder originating from animal (8%) and plant (4%) sources [2]. Microbial proteases account for approximately 40% of total worldwide sales of enzymes [3]. Processes that can be used for microbial protease production include submerged fermentation (SmF) and solid-state fermentation (SSF). The latter is particularly advantageous for enzyme production by filamentous fungi, since it simulates the natural habitat of these microorganisms [4, 5]. Another advantage of SSF is that agroindustrial wastes (oil cakes, bagasse, wheat bran, etc.) can be used as the solid substrate, acting as sources of both carbon and energy. However, certain operational limitations of SSF, such as
%U http://www.hindawi.com/journals/isrn.microbiology/2013/369082/