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Biocellulose ( BC) is pure extracellular cellulose produced by several species of micro-organisms that has numerous applications in the food, biomedical and paper industries. However, the existing biocellulose-producing bacterial strain with high yield was limited. The aim of this study was to isolate and identify the potential biocellulose-producing bacterial isolates from Malaysian acidic fruits. One hundred and ninety-three bacterial isolates were obtained from 19 local acidic fruits collected in Malaysia and screened for their ability to produce BC. A total of 15 potential bacterial isolates were then cultured in standard Hestrin-Schramm ( HS) medium statically at 30°C for 2 weeks to determine the BC production. The most potent bacterial isolates were identified using 16S rRNA gene sequence analysis, morphological and biochemical characteristics. Three new and potent biocellulose-producing bacterial strains were isolated from soursop fruit and identified as Stenotrophomonas maltophilia WAUPM42 , Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. Stenotrophomonas maltophilia WAUPM42 was the most potent biocellulose-producing bacterial strain that produced the highest amount of BC 0·58 g l−1 in standard HS medium. Whereas, the isolates P. vagans WAUPM45 and B. fluminensis WAUPM53 showed 0·50 and 0·52 g l−1 of BC production, respectively. Significance and Impact of the Study Biocellulose ( BC) is pure extracellular cellulose that is formed by many micro-organisms in the presence of carbon source and acidic condition. It can replace plant-based cellulose in multifarious applications due to its unique characteristics. In this study, three potential biocellulose-producing bacterial strains were obtained from Malaysian acidic fruits and identified as Stenotrophomonas maltophilia WAUPM42 , Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. This study reports for the first time the new biocellulose-producing bacterial strains isolated from Malaysian acidic fruits. [ABSTRACT FROM AUTHOR]

Aims: This study aimed at investigating the anti- Malassezia activity of xanthorrhizol (XTZ) isolated from Curcuma xanthorrhiza Roxb. against Malassezia furfur ATCC 14521 and Malassezia pachydermatis ATCC 14522. Methods and Results: The in vitro susceptibility tests for XTZ were carried out in terms of minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC), using broth microdilution method with endpoint after 48 h. Time-kill curves were determined at concentrations ranging from 0 to 25 μg ml−1. The MIC values of XTZ against M. furfur and M. pachydermatis were 1·25 and 0·25 μg ml−1, respectively. The MFC of XTZ was 5 μg ml−1 for M. furfur and 2·5 μg ml−1 for M. pachydermatis. Time-kill curves demonstrated that treatment with 25 μg ml−1 of XTZ for 5 h was able to kill 100% of M. furfur, while 20 μg ml−1 of XTZ for 15 min killed M. pachydermatis completely. Conclusion: XTZ shows potential as an anti- Malassezia agent for inhibiting the growth of M. furfur ATCC 14521 and M. pachydermatis ATCC 14522 in vitro. Significance and Impact of the Study: XTZ may be a useful alternative for treating Malassezia-associated diseases. [ABSTRACT FROM AUTHOR]

Aims: The purpose of this study was to search for a novel quorum sensing inhibitor and analyse its inhibitory activity. Methods and Results: Quorum sensing inhibition was monitored using the Tn- 5 mutant, Chromobacterium violaceum CV026. Vanilla beans ( Vanilla planifolia Andrews) were extracted using 75% (v/v) aqueous methanol and added to C. violaceum CV026 cultures. Inhibitory activity was measured by quantifying violacein production using a spectrophotometer. The results have revealed that vanilla extract significantly reduced violacein production in a concentration-dependent manner, indicating inhibition of quorum sensing. Conclusions: Vanilla, a widely used spice and flavour, can inhibit bacterial quorum sensing. Significance and Impact of the Study: The results suggest that the intake of vanilla-containing food materials might promote human health by inhibiting quorum sensing and preventing bacterial pathogenesis. Further studies are required to isolate specific substances from vanilla extract acting as quorum sensing inhibitors. [ABSTRACT FROM AUTHOR]

Aims: We determined the effect of xanthorrhizol (XTZ) purified from the rhizome of Curcuma xanthorrhiza Roxb. on the Streptococcus mutans biofilms in vitro. Methods and Results: The biofilms of S. mutans at different phases of growth were exposed to XTZ at different concentrations (5, 10 and 50 μmol l−1) and for different time exposures (1, 10, 30 and 60 min). The results demonstrated that the activity of XTZ in removing S. mutans biofilm was dependent on the concentration, exposure time and the phase growth of biofilm. A concentration of 5 μmol l−1 of XTZ completely inhibited biofilm formation by S. mutans at adherent phases of growth, whereas 50 μmol l−1 of XTZ removed 76% of biofilm at plateau accumulated phase when exposed to S. mutans biofilm for 60 min. Conclusions: Xanthorrhizol isolated from an edible plant ( C. xanthorrhiza Roxb.) shows promise as an antibacterial agent for inhibiting and removing S. mutans biofilms in vitro. Significance and Impact of the Study: XTZ could be used as a potential antibacterial agent against biofilm formation by S. mutans. [ABSTRACT FROM AUTHOR]