Microbial proteases, especially from Bacillus spp., have enormously been exploited for a broad variety of applications such as for physiological processes, food and feedstuff, detergents, as well as in the pharmaceutical and leather. In this work, proteases produced by the thermophilic Bacillus sp. SMIA-2 submerged cultures were spray-dried in an attempt to improve its stability for applications in industry. The enzymatic extract was dried using drying adjuvants, and optimal conditions for preserving enzymatic activity were studied following a statistical experimental design. The spray process factors studied were the drier air inlet temperature and the adjuvants concentrations. The responses analyzed were the enzymatic activity and mass recovered of the powder after spray drying. Additionally, the stability of the powder was assessed during 180 days at room temperature. The results revealed that satisfactory levels of enzymatic activity were obtained when 0.5% (w/v) carboxymethylcellulose and 1.0% (w/v) maltodextrin were incorporated to enzymes solutions and the spray drier inlet temperature was 110 ºC. Furthermore, this dried protease extracts showed potential for future commercial applications because of their stability at room temperature for 180 days.

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Context The feeding of pigs raised in an intensive system has been made, in general, with rations formulated using corn and soybean meal as the main ingredients. Brown rice bran, a by-product of the processing of rice grains for human consumption, presents itself as an alternative for total or partial replacement. Aims The objective of the present study was to observe the effects of including 10% of whole rice bran (WRB), adding 0.02% exogenous multienzyme complex (MC) and changing the levels of metabolisable energy and available phosphorus (ME.aP) together in rations for newly weaned piglets. Methods Digestibility and metabolisability of the rations, as well as zootechnical performance, were evaluated using 24 and 144 animals respectively, distributed in randomised blocks in time, with eight treatments, in a 2 × 2 × 2 factorial scheme. Three repetitions were used in the metabolism essay, with one animal housed per cage, and six repetitions were made in the performance test, with three animals per stall, which was considered the experimental unit. Digestibility and metabolisability coefficients, weight gain and feed intake, as well as feed efficiency, were evaluated. Key results The results showed that the inclusion of WRB reduced the digestibility and metabolisability coefficients of the rations, while the addition of MC provided an improvement in these indexes. The performance test showed that the inclusion of WRB worsened (P < 0.05) the feed efficiency. Conclusions and implications The multienzyme complex improves the digestibility and metabolisability of experimental rations, although it does not influence the performance of piglets in the nursery phase.