Aims: Banana peel (BP) waste is still underutilized in Malaysia, which can be used as source of renewable energy. Microbial fuel cell (MFC) is a device that utilizes biomass to convert chemical energy into electrical energy with help of the microbial catalysis. The present study evaluates the current generation of MFC supplemented with BP waste as substrate for Pseudomonas aeruginosa ATCC 27853. Methodology and results: The CHNS result shows that the C:N ratio of BP is 27:1 which is within the optimum C:N ratio for the microbial food requirement. Fluctuation of current increases as concentration of banana peel extract (BPE) decreases from 1:10, 1:20, 1:40 and 1:80, thus making 1:10 BPE optimum. Current fluctuation is related to microbial activity due to the sufficiency of nutrients which subsequently affect the performance of MFC. BPE and banana peel slurry (BPS) comparison shows that BPS is optimum. BPE reaches a maximum current of 3.91 µA in ascending phase which is higher compared to BPS (3.65 µA). In descending phase, BPE current drops to 2.31 µA compared to 2.98 µA of BPS. In stationary phase, BPS able to maintain a higher current compared to BPE. MFC maximum current was doubled to 6.52 µA when PEM was treated priorly. Conclusion, significance and impact of study Besides exploring and improving the ability of MFC as an alternative for power production other than fossil fuel, this research also encourage society to fully utilize waste as a source of renewable energy instead of throwing it into garbage without productivity.

Aims: Streptococcus pneumoniae is one the world’s foremost bacterial pathogens that cause massive global mortality and morbidity in young children and immunocompromised adults especially in developing countries. Biofilms have been increasingly recognized as an important prerequisite to disease. Individual S. pneumoniae strains differ markedly in their virulence phenotypes, but genetic heterogeneity has complicated attempts to identify any association between a given clonal lineage and propensity to cause a particular disease type. This study investigated serotype 19 S. pneumoniae from blood and ear isolates for biofilm formation capacity in relation to isolate source, pH and ferric oxide [Fe(III)] supplementation. Methodology and results: Viable count and density biofilm assays, microscopy and multi locus sequence typing (MLST) were applied to investigate biofilm formation capacity and genetic diversity of serotype 19 S. pneumoniae from blood and ear isolates. Generally, blood isolates were observed to produce more biofilms at both pH 7.4 and 6.8 compared to the ear isolates. The supplementation of Fe(III) was also found to support biofilm growth. Upon MLST typing of the isolates, marked differences in biofilm formation within the same sequence types (ST) of ST199 and ST177 was observed. This strongly indicated that strains within the same sequence type show differences in biofilm formation capacity. Conclusion, significance and impact of study This study showed that despite belonging to the same serotype, serotype 19, S. pneumoniae blood and ear isolates showed high diversity in biofilm formation ability in relation to pH and Fe(III) supplementation. Additionally, pneumococcal isolates from sequence types ST199 and ST177 also gave rise to differences in biofilm formation ability within the same sequence type (ST). The diversity of biofilm formation within serotype 19 seen in this study is significant to further inform of vaccination strategies against pneumococcal infections, in that due to variations in biofilm formation capacity within the same ST. It is possible that within serotype 19 may show variable vaccination or drug treatment responses. This also indicates that the current treatment strategy which employs specific serotype selection as for PCV14 and PCV7 pneumococcal vaccines may not produce the desired therapeutic results.
Streptococcus pneumoniae--immunology ; Biofilms--radiation effects