RESUMO: Foram avaliadas a ação de celulases e pectinases comerciais e não comerciais na hidrólise de casca de soja (CS) e palha e espigas de milho (PEM), o efeito da temperatura e da agitação na hidrólise do substrato lignocelulósico e as características bromatológicas dos substratos hidrolisados. O efeito do pré-tratamento na hidrólise de resíduos lignocelulósicos e a análise bromatológica também foram avaliados. A maior atividade hidrolítica ocorreu a 300 rpm para CS (47,95 e 51,43% para celulase e pectinase, respectivamente) e a 350 rpm para PEM (26,05 e 9,23% para celulase e pectinase, respectivamente). As enzimas não comerciais atingiram 7,26-30% da quantidade de hidrólise obtida com as enzimas comerciais, nos mesmos substratos. O pré-tratamento com 7,5% de NaOH e um tamanho de partícula do substrato de 0,5 mm aumentou significativamente a hidrólise de CS e PEM para ambas as enzimas. As características bromatológicas mostraram que a casca de soja hidrolisada com celulase e pectinase comercial tem potencial para uso em larga escala na produção de ração animal.

ABSTRACT: This study evaluated the action of commercial and non-commercial cellulases and pectinases in the hydrolysis of soybean hulls (SH) and corn stover and cobs (CSC), the effect of temperature and agitation on the lignocellulosic substrate hydrolysis and the bromatological characteristics of hydrolyzed substrates. The effect of pretreatment on the hydrolysis of lignocellulosic residues and bromatological analysis were also evaluated. The highest hydrolytic activity occurred at 300 rpm for SH (47.95 and 51.43% for cellulase and pectinase, respectively) and at 350 rpm for CSC (26.05 and 9.23% for cellulase and pectinase, respectively). Non-commercial enzymes achieved 7.26-30% of the amount of hydrolysis obtained with commercial enzymes, on the same substrates. Pretreatment with 7.5% of NaOH and a particle size of the substrate of 0.5 mm significantly increased the hydrolysis of SH and CSC for both enzymes. The bromatological characteristics showed that soybean hulls hydrolyzed with both commercial cellulase and pectinase have potential for large-scale use in animal feed production.

ABSTRACT. The aim of this study was to evaluate the action of commercial and non-commercial cellulase and pectinase on rice husk and Tifton 85 hay hydrolyses. The hydrolysis kinetics of the substrates with commercial cellulase and pectinase were evaluated and the hydrolysis at different temperature and agitation conditions was maximized using experimental design. The combined use of commercial and non-commercial enzymes under optimized conditions was evaluated. The pre-treatment of the residues was also investigated by milling and different concentrations of NaOH. Finally, the effect of the hydrolysis on the bromatological composition of the residues was evaluated. The best hydrolysis times of rice husk and Tifton 85 hay were 10 and 12h for commercial cellulase, 12 and 14h for non-commercial cellulase, 10 and 14h for commercial pectinase and 16 and 20h for non-commercial pectinase, respectively. The highest hydrolysis values were obtained using commercial cellulase with 1:50 (w:v enzyme:water) dilution rate, at 45ºC and 300 rpm agitation for both substrates, reaching 20.6% maximum percentage for Tifton 85 hay and 11.6% for rice husk. The combined use of commercial enzymes did not increase hydrolysis percentage. The pre-treatment using 7.5% NaOH and 0.5 mm grain size significantly increased the rice husk and Tifton 85 hay hydrolyses (60-80%), either using commercial cellulase or pectinase enzymes. The use of non-commercial enzymes provided 18-30% hydrolysis obtained from commercial ones. Bromatological analyzes indicated a reduction in neutral detergent fiber and acid detergent fiber content for rice husk and Tifton 85 hay when using pectinases and commercial cellulases.