Marine microorganisms are known to withstand adverse conditions, which make them potentially useful for bioconversions. In a recent study, cellulolytic species of Bacillus (B. albus, B. thurigiensis) and Lysinibacillus (L. borontolerance, L fulsiformis, L. sphaerocus, L. xylanilyticus) were isolated from the Atlantic Ocean coastal sediments in Nigeria. Considering the potential biotechnological applications of these bacteria, the study was extended to focus on the extent of their cellulose-degradation and cellulase activity capabilities. Obeche (Tryplochiton scleroxylon) wood was exposed to the organisms in Mineral Salts Medium (MSM) for 16 weeks and examined for weight losses before microchemical tests were conducted on the wood sections to detect the component(s) attacked. Whatman Filter Paper was also similarly exposed to the bacteria, but for only 72 h. Supernatants from MSM- and seawater-carboxyl methyl cellulose (CMC) broth were tested for cellulase activities with CMC and were monitored daily for 7 days. Lowry method was used to determine protein concentrations in the medium after which specific cellulase activities were calculated. The organisms caused weight losses in submerged and partially submerged wood, which were not significantly different (20.5-26.1 vs 21.1-25.7%). Microchemical analyses showed that cellulose was degraded by all the organisms while lignin was partially attacked. Filter paper degradation was indicated by weight losses of 3.28-4.18% in 72 h. Cellulase activity values obtained from MSM-CMC broth after 24 h stood at 6.94±0.8-9.79±1.1 U/ml and except for L. borontolerance (P=0.040), they were not significantly different from seawater-CMC broth-derived cellulases (7.75±0.8-9.46±1.2 U/ml). The cellulase activities peaked on the 4th day (27.75-34.11 U/ml). Specific cellulase activity was 2.14-4-03 on the 1st day and 8.21-16.89 U/mg by the 7th day. Thus, the capabilities of species of Bacillus and Lysinibacillus to degrade cellulose and produce substantial cellulases are demonstrated. Purification can enhance the enzymes’ activities and make them potentially suitable for biotechnological applications.
