achieved when grown on XY (12.3 mIU ml−1 ± 0.6), corresponding to specific activities of 0.85 IU mg−1 and 0.61 IU mg−1 , respectively (total intracellular protein content of 0.12 mg ml−1 for CMC culture and 0.2 mg ml−1 for XY culture). Also, some -xylosidase activity (1.5 mIU ml−1 ± 1.1) was detected in supernatant from XY culture, while no -glucosidase activity was evidenced either in MM-XY or MM-CMC culture supernatants. Based on its high xylanolytic potential, temperature and pH dependence assays were carried out in order to characterize the extracellular xylanolytic activ- ity of Paenibacillus sp. A59. High relative activity (over 75%) was achieved in a range from pH 5 to 11, with two peaks of optimal activity at pH 6 and pH 10. Optimal temperature occurred between 50 ◦ C and 70 ◦ C, retaining more than 60% activity at 80 ◦ C (Fig. 4) which is remarkable for a mesophile isolate. Moreover, the enzy- matic extract retained more than 60% activity after 48h at 50◦C, indicating thermal tolerance.