Microbial diversity in Mt. Makiling [Los Banos, Laguna, Philippines] and its biotechnological exploitation

Series of soil and mud samplings were done at the mudspring of Mt. Makiling, Philippines to explore potential sources of enzyme-producing thermophilic microorganisms. From the 410 isolates studied, 19.55 percent have optimum growth temperature at 30 deg C, 34.24 percent at 45 deg C, 26.10 percent at 55 deg C and 20.10 percent at 65 deg C. Among the 330 thermophilic (45 deg to 65 deg C) isolates, 15.54 percent produced acids. Proteolytic activity was exhibited by the 58 thermophilic bacteria after 24 hr. at 45 deg C, 15 isolates at 55 deg C and 4 isolates at 65 deg C. Test for the production of neutral protease activity in casein revealed that 4 isolates (39.80 NPU/ml for MB-11; 10.15 NPU/ml for MB-59; 10.00 NPU/ml for SB-46 and 9.88 NPU/ml for MB-8) exhibited 2.7 to 10.8 times higher neutral protease unit per ml (NPU/ml) than that produced by Bacillus stearothermophilus (3.69 NPU/ml) reported by Takei, et al. (1987). Cellulolytic activity of the thermophilic bacteria and yeasts were found to be mostly exhibiting disintegration reaction on cellulose azure, indicating that other cellulose components were present. Further tests showed detectable activity of CMCase assay. Amylolytic activity, on the other hand, was exhibited by a total of 115 thermophilic isolates out of the 410 isolates that were tested for hydrolysis of starch. This includes 47 out of 118 bacterial isolates (25 percent), 55 out of 112 actinomycetes (49 percent), 12 out of 55 mold isolates (22 percent) and 1 out of 55 yeast isolates. All the isolates that exhibited positive results in amylase production were then subjected to saccharification screening to determine their saccharifying efficiency. Quantitative analysis results showed that sample MB-11 (for bacteria), S5A74 (for actinomycetes) and S5M-16 (for molds) showed the highest concentration values of 0.35, 0.30 and 0.60 mg glucose/ml, respectively. The lone yeast isolate that tested positive in amylase exhibited a concentration value of 0.21 mg glucose/ml. Preliminary identification tests showed that the probable genera of the thermophilic bacterial isolates were Bacillus (aerobic and facultative anaerobes species), Flavobacterium, Planococcus, and Pseudomonas. Among the 112 strains of Actinomycetes, 55 has the LL-type diaminopimelic acid (DAP) isomers while 55 has meso-type DAP. The meso-type was characterized and found to be belonging to Actinomadurra sp. (4 strains), Dactylosporium sp. (1 strain), Microbispora sp. (5 strains), Micromonospora sp. (5 strains), Nocardia sp. (10 strains), and Streptospoangium sp. (3 strains). The 29 strains of the meso-type DAP strains are in the process of identification. It is presumed that the novo species are isolated from the mudsprings of Mt. Makiling