Optimizing the catalytic activities of methanol and thermotolerant Kocuria flava lipases for biodiesel production from cooking oil wastes.

In this study, two highly thermotolerant and methanol-tolerant lipase-producing bacteria were isolated from cooking oil and they exhibited a high number of catalytic lipase activities recording 18.65 ± 0.68 U/mL and 13.14 ± 0.03 U/mL, respectively. Bacterial isolates were identified according to phenotypic and genotypic 16S rRNA characterization as Kocuria flava ASU5 (MT919305) and Bacillus circulans ASU11 (MT919306). Lipases produced from Kocuria flava ASU5 showed the highest methanol tolerance, recording 98.4% relative activity as well as exhibited high thermostability and alkaline stability. Under the optimum conditions obtained from 3D plots of response surface methodology design, the Kocuria flava ASU5 biocatalyst exhibited an 83.08% yield of biodiesel at optimized reaction variables of, 60 â—‹C, pH value 8 and 1:2 oil/alcohol molar ratios in the reaction mixture. As well as, the obtained results showed the interactions of temperature/methanol were significant effects, whereas this was not noted in the case of temperature/pH and pH/methanol interactions. The obtained amount of biodiesel from cooking oil was 83.08%, which was analyzed by a GC/Ms profile. The produced biodiesel was confirmed by Fourier-transform infrared spectroscopy (FTIR) approaches showing an absorption band at 1743 cm-1, which is recognized for its absorption in the carbonyl group (C=O) which is characteristic of ester absorption. The energy content generated from biodiesel synthesized was estimated as 12,628.5 kJ/mol. Consequently, Kocuria flava MT919305 may provide promising thermostable, methanol-tolerant lipases, which may improve the economic feasibility and biotechnology of enzyme biocatalysis in the synthesis of value-added green chemicals.

No molecular evidence of MERS-CoV circulation in Jeddah, Saudi Arabia between 2010-2012: a single-center retrospective study.

INTRODUCTION: Middle East respiratory syndrome coronavirus (MERS-CoV) is an emerging zoonotic viral pathogen and a serious public health concern. The virus was first reported in Saudi Arabia in 2012 and continues to be endemic in the region. Most of the initial MERS-CoV cases in 2012 and early 2013 were sporadic, and it remains unclear whether MERS-CoV was circulating before 2012 or not. Therefore, we tried here to find any molecular evidence of MERS-CoV circulation in humans before or during 2012 in the city of Jeddah, Saudi Arabia. METHODOLOGY: We examined 349 archived respiratory samples collected between January 2010 and December 2012 from patients with acute respiratory illnesses from the city of Jeddah in Western Saudi Arabia. All samples were screened for MERS-CoV by real-time RT-PCR targeting the upstream E-gene (UpE) and the open reading frame 1 a (ORF1a). RESULTS: All tested samples which were originally found negative for influenza A H1N1 virus were also found to be negative for MERS-CoV. CONCLUSIONS: These results suggest that circulation of MERS-CoV was uncommon among patients with acute respiratory symptoms in Western Saudi Arabia between 2010 and 2012.