In present study, purification and characterization of two alpha-glucosidases from termite workers Macrotermes bellicosus (Termitidae: Macrotermitinae) were conducted. The purification procedure consisted of anion-exchange, gel filtration, and hydrophobic interaction chromatography. The enzymes designated alpha-glucosidases A1 and A2 had native molecular weights of approximately 191.23± 0.7 and 140.39± 1.2 kDa, respectively, and there functioned as monomeric structures. The two isoforms isolated exhibited maximal alpha-glucosidase activity pH at 5.6. Alpha-glucosidases A1 and A2 hydrolytic activities were maximal at 50 and 45°C, respectively. The purified enzymes pH stabilities were in the range of 5.0-6.0. The enzymes readily hydrolyzed p-nitrophenyl-α-D-glucoside, maltose, maltodextrins and required strictly alpha-gluco configuration for activity. They cleaved glucose-glucose alpha-(1–2) linkages better than alpha-(1–4), alpha-(1–1), alpha-(1–3) and β-(1–6) linkages. The catalytic efficiency (Vmax/ KM) values for p-nitrophenyl-α-D-glucoside, were respectively 277.75±9.2 and 59.51±4, for alpha-glucosidases A1 and A2. Both alpha-glucosidases were inhibited by sulfhydryl-binding reagents. The physiological role of the two alpha-glucosidases in the digestive tract of the termite could be the digestion of di-and oligosaccharides derived from starch. The enzymes could be used as a tool in the structural analysis of D-glucose containing oligosaccharide chains of glycoproteins, glycolipids and starch.
Heavy metals resistant bacteria were obtained from wastewater samples in mining sites of Itogon, Benguet, Philippines. The isolates were cultured in a medium with different concentrations of copper (Cu), chromium (Cr), nickel (Ni), zinc (Zn) and lead (Pb). Out of the 150 initial isolates, the 4 isolates, which survived in each 100 ppm of Zn, Cr, Pb, and Ni exhibited high metal resistance and were identified at the Philippine Genome Center (UP Diliman, Quezon City, Philippines) as isolates A). Acinetobacter sp. junii, B). Acinetobacter sp. tandoii, C). Bacillus cereus, D). Bacillus toyonensis. Sample digestion with HCl showed higher heavy metal reduction results compared with the undigested, thus suggesting that acid treatment gave better extraction of metal components prior to Atomic Absorption Spectroscopy. Biosorption of heavy metals were highest in 75 ppm of lead. Results showed that the isolate Bacillus toyonensis can reduce lead by 92.43 % in 5 days at room temperature.