Isolation and Partial Characterisation of Thermophilic Cellulolytic Bacteria from North Malaysian Tropical Mangrove Soil.

This study reports the biodiversity of thermophilic cellulolytic bacterial strains that present in the north Malaysian mangrove ecosystem. Soil samples were collected at the four most northern state of Malaysia (Perak, Pulau Pinang, Kedah and Perlis). The samples obtained were first enriched in nutrient broth at 45°C and 55°C prior culturing in the carboxymethylcellulose (CMC) agar medium. Repeated streaking was performed on the CMC agar to obtain a pure culture of each isolate prior subjecting it to hydrolysis capacity testing. The isolates that showing the cellulolytic zone (halozone) were sent for 16S rRNA sequencing. Total seven isolates (two from Perak, three from Kedah, another two were from Perlis and Penang each) showed halozone. The isolate (KFX-40) from Kedah exhibited highest halozone of 3.42 ± 0.58, meanwhile, the one obtained from Perak (AFZ-0) showed the lowest hydrolysis capacity (2.61 ± 0.10). Based on 16S rRNA sequencing results, 5 isolates (AFY-40, AFZ-0, KFX-40, RFY-20, and PFX-40) were determined to be Anoxybacillus sp. The other two isolates were identified as Bacillus subtilis (KFY-40) and Paenibacillus dendritiformis (KFX-0). Based on growth curve, doubling time of Anoxybacillus sp. UniMAP-KB06 was calculated to be 32.3 min. Optimal cellulose hydrolysis temperature and pH of this strain were determined to be 55°C and 6.0 respectively. Addition of Mg2+ and Ca2+ were found to enhance the cellulase activity while Fe3+ acted as an enzyme inhibitor.

Nutrient improvement using statistical optimization for growth of Schizophyllum commune, and its antifungal activity against wood degrading fungi of rubberwood.

Two statistical tools, Plackett-Burman design (PBD) and Box-Behnken design (BBD) were used to optimize the mycelia growth of Schizophyllum commune with different nutrient components. Results showed that 32.92 g/L of biomass were produced using a medium consisting of 18.74 g/L yeast extract, 38.65 g/L glucose, and 0.59 g/L MgSO(4).7H(2)O. The experimental data fitted well with the model predicted values within 0.09 to 0.77% error. The biomass was also tested for antifungal activity against wood degrading fungi of rubberwood. Results showed that the minimum inhibitory concentration (MIC) values for antifungal activity range from 0.16 to 5.00 µg/µL. The GC-MS analysis indicated that this fungus produced several compounds, such as glycerin, 2(3H)-furanone, 5-heptyldihydro-, 4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl-, and triacetin.