Noor Aini Abdul Rashid

Communal microaerophilic-aerobic biodegradation of Amaranth by novel NAR-2 bacterial consortium.

A novel bacterial consortium, NAR-2 which consists of Citrobacter freundii A1, Enterococcus casseliflavus C1 and Enterobacter cloacae L17 was investigated for biodegradation of Amaranth azo dye under sequential microaerophilic-aerobic condition. The NAR-2 bacterial consortium with E. casseliflavus C1 as the dominant strain enhanced the decolorization process resulting in reduction of Amaranth in 30 min. Further aerobic biodegradation, which was dominated by C. freundii A1 and E. cloacae L17, allowed biotransformation of azo reduction intermediates and mineralization via metabolic pathways including benzoyl-CoA, protocatechuate, salicylate, gentisate, catechol and cinnamic acid. The presence of autoxidation products which could be metabolized to 2-oxopentenoate was elucidated. The biodegradation mechanism of Amaranth by NAR-2 bacterial consortium was predicted to follow the steps of azo reduction, deamination, desulfonation and aromatic ring cleavage. This is for the first time the comprehensive microaerophilic-aerobic biotransformation pathways of Amaranth dye intermediates by bacterial consortium are being proposed.

Genome Sequence of Pichia kudriavzevii M12, a Potential Producer of Bioethanol and Phytase

ABSTRACT A draft genome sequence of Pichia kudriavzevii M12 is presented here. The genome reveals the presence of genes encoding enzymes involved in xylose utilization and the pentose phosphate pathway for bioethanol production. Strain M12 is also a potential producer of phytases, enzymes useful in food processing and agriculture.

Genome sequence of aureobasidium pullulans AY4, an emerging opportunistic fungal pathogen with diverse biotechnological potential

ABSTRACT Aureobasidium pullulans AY4 is an opportunistic pathogen that was isolated from the skin of an immunocompromised patient. We present here the draft genome of strain AY4, which reveals an abundance of genes relevant to bioindustrial applications, including biocontrol and biodegradation. Putative genes responsible for the pathogenicity of strain AY4 were also identified.

Genome Sequence of Citrobacter sp. Strain A1, a Dye-Degrading Bacterium

Citrobacter sp. strain A1, isolated from a sewage oxidation pond, is a facultative aerobe and mesophilic dye-degrading bacterium. This organism degrades azo dyes efficiently via azo reduction and desulfonation, followed by the successive biotransformation of dye intermediates under an aerobic environment. Here we report the draft genome sequence of Citrobacter sp. A1.

Candida orthopsilosis and Aureobasidium pullulans: Rare Fungal Pathogens Causing Persistent Skin Infection

Rare fungal human skin pathogens, identified as Candida orthopsilosis and Aureobasidium pullulans were co-isolated from patient with persistant cutaneous skin infection in Singapore. This significant discovery offers knowledge to the scientific and medical community in order to stimulate research interest and to address treatment regimes of fungal infection.

Genome Sequence of Enterococcus sp. Strain C1, an Azo Dye Decolorizer

Enterococcus sp. strain C1 is a facultative anaerobe which was coisolated with Citrobacter sp. strain A1 from a sewage oxidation pond. Strain C1 could degrade azo dyes very efficiently via azo reduction and desulfonation in a microaerophilic environment. Here the draft genome sequence of Enterococcus sp. C1 is reported.

Identification of Biodegradation Related Genes from Bacterial Consortium NAR-2

In this study, PCR amplification of biodegradation related genes from NAR-2 bacterial consortium was accomplished. NAR-2 bacterial consortium consists of Citrobacter freundii A1, Enterococcus casseliflavus C1 and Enterobacter cloacae L17. The amplified genes were sequenced, bioinformatically analyzed and compared with the sequences from GenBank database of National Centre of Biotechnology Information (NCBI) using BLASTn and BLASTp search tools. The assembled sequences represented almost >70% of similarity to biodegradation related genes. These genes may act as a key intermediate enzyme in biodegradation pathway.

Effect of pH and biological media on polyvinylpyrrolidone-capped silver nanoparticles

Toxicity and mobility of silver nanoparticles (AgNPs) vary in different surrounding environments. Surface coatings or functionalization, temperature, pH, dissolved oxygen concentration, nanoparticle concentration, the presence of organic matter, and ionic strength are factors which dictate the transformation of AgNPs in terms of aggregation and stabilization. Thus, the purpose of this study is to investigate the behavior of polyvinylpyrrolidone (PVP)-capped AgNPs at different pHs (pH 2 to 10) and in different biological media (0.1 M phosphate buffer, nutrient broth, P5 and modified P5 media) analyzed using UV-Vis spectroscopy and zeta potential analyzer. The PVP-capped AgNPs changed its behavior in the presence of varying media, after 24 h incubation with shaking at 200 rpm at 30°C. No aggregation was observed at pH 4 to 10, but distinctive at very low pH of 2. Low pH further destabilized PVP-capped AgNPs after 24 h of incubation. High ionic strength 0.1 M phosphate buffer also resulted in slow aggregatio...

In silico analyses of flavin reductase from citrobacter freundii A1

Objective: The aim of the present study was to describe the structural and phylogenetic features of flavin reductase from C.freundii Al using bioinfonnatics tools. Materials and methods:The flavin reductase (Ire) gene from a dye-degrading bacterium, C. freundii Al was isolated and amplified by Polymerase Chain Reaction (peR). The gene encodes for NAD(P)H:flavin oxidoreductase, an enzyme that catalyzes the reduction of soluble flavins by reduced pyridine nucleotides this was believed to be the azoreductase from C. freundii AI. The gene, approximately 0.8 kb was sequenced and in silica analyses of the nucleotide sequence were performed. Results: From phlyogenetic analyses, we observed that flavin reductase enzyme generally existed in most microorganisms and the enzyme from C.freundii Al is conserved among the Gram-negative bacteria. The protein function of the flavin reductase coded was predicted based on the motifs of deduced amino acid sequence. The amino acid sequence of flavin reductase from C. freundii Al was compared with other azoreductases and was found to be a unique NADPH-preferred azoreductase. Conclusion: Hence, in silica characterization of flavin reductase gene presented various features of the gene and this would facilitate molecular studies of the gene and reveal the functional role of the enzyme.