South Asian Journal of Research in Microbiology

Aim: The present study was taken up to establish the effect of niacinamide on phenoloxidase lead melanogenesis and to prove the reliability of C. neoformans based screening methodology.

Methods: The organism was grown in the Minimal media in presence and absence of L- DOPA and Niacinamide and checked for its pigment producing ability at different time intervals.

Results: Niacinamide did not affect the pigmentation in Cryptococcus neoformans in the absence or presence of L-Dopa.

Conclusion: Cryptococcus neoformans as a biological tool for studying the mechanism of action of various melanin promoters/ inhibitors. The present study highlights the importance and usefulness of Cryptococcus neoformans based screening invention as it is cost effective rapid and ‘living cell model’.

Water and soil samples were cultured on Cetrimide agar, Kings B agar, and nutrient agar supplemented with 50 μg.mL^-1 chloramphenicol for the isolation of greenish pigment producing Pseudomonas species. Greenish pigment producing colonies that grew on the media were subjected to microscopic examination and selected physicochemical/biochemical tests to confirm that they belong to the Pseudomonas genus. Isolates confirmed to belong to the Pseudomonas genus were subjected to antibiotic susceptibility testing to various antibiotics using the disc diffusion method. The antibiotic sensitivity testing showed that two of the Pseudomonas isolates from nutrient agar plates supplemented with chloramphenicol showed resistance to Ampiclox, Rifampicin, and Norfloxacin. Also, one of the isolates showed resistance to Gentamycin, Amoxicillin, and Amoxicillin clavulanate. Two of the isolates from Kings B medium showed resistance to Ampiclox; another isolate showed resistance to Rifampicin, and one of the isolate that showed resistance to Ampiclox also showed resistance to Rifampicin, Chloramphenicol and Norfloxacin. Only one isolate from Cetrimide agar showed resistance to Ofloxacin and Nalidixic acid. Based on the EUCAST Breakpoint Table for P. aeruginosa, 12 out of the 14 Pseudomonas isolates (85.7%) were susceptible to Levofloxacin and Gentamycin, while 8 (57.1%) of the isolates were susceptible to Ciprofloxacin. The results indicate that Pseudomonas species isolated from the environment through the use of differential and selective media can become resistant to some antibiotics, and that Levofloxacin and Gentamycin could be used in the treatment of infections caused by antibiotic resistant Pseudomonas.

Typha australis (Typha grass) obtained from Kware Lake was used in this research to produce bioethanol. Different pretreatment methods including dilute acid (0.2M H₂SO₄), dilute alkaline (0.2M NaOH) and liquid hot water pretreatments were used to pretreat the Typha grass sample before enzymatic saccharification for 7 days using Aspergillus niger isolated from soil sediment and the hydrolysate was seeded with Saccharomyces cerevisiae isolated from palm wine to produce bioethanol. HPLC was used to analyze bioethanol product. The result showed that pretreatment with 0.2M H₂SO₄ removed more hemicelluloses (7.0%) when compared with other pretreatment methods used, but pretreatment with 0.2M NaOH and liquid hot water removed more lignin (14.29%) than dilute acid pretreatment. The highest percentage reducing sugar concentration of 0.58% was obtained from lower part of the sample pretreated with liquid hot water while Typha grass pretreated with 0.2M H₂SO₄ and 0.2M NaOH produced the highest percentage reducing sugar concentration of 0.32% each from the upper part of the sample. Also, the highest Bioethanol concentration of 2.07% was obtained at day 6 of fermentation from the Typha grass pretreated with liquid hot water while Typha grass pretreated with 0.2M H₂SO₄ and 0.2M NaOH produced highest Bioethanol concentration of 0.43% and 0.54% respectively. The results indicate that Typha grass can be harnessed for bioethanol production thereby reducing their negative impact on Lakes.

Hepatitis B is a life threatening infectious liver disease caused by hepatitis B virus (HBV). The aim of this study was to determine the prevalence of HBV among food vendors in Wurukum, a highly commercial section of metropolitan Makurdi in Benue State. The test was carried out with the use of an immunochromatographic  micropoint HBsAg test strips and a HBsAg  buffer screen for the virus. Out of the 250 non-vaccinated food vendors sampled, 27(10.8%) had HBV infection, with more in males (21.7%) than in females (6.6%). No significant difference (p>0.05) was found among age groups in spite of the observed highest prevalence of 14.3% among the 20-29 year olds. Therefore, the need for routine screening cannot be overemphasized in spite of known risk factors among food vendors.

Aim: This study was carried out to determine the ability of Aspergillus niger to break down theobromine in cocoa by-products, for its possible use in animal feeds.

Place and Duration of Study: Department of Biological Sciences, Wesley University, Ondo, Ondo State, Nigeria between January 2013 and June 2013.

Methodology: Cocoa by-products (combination of cocoa bean shell (CBS) and cocoa bean meal (CBM)) was milled into fine particle size, sterilized and fermented with Aspergillus niger for 5 days. The theobromine content was monitored at 24 h interval during fermentation and proximate analyses were carried out before and after the fermentation process.

Results: Significant reduction of theobromine content of 78.13% was observed after 5 days of fermentation. The crude protein and crude ash content increased by 2.7% and 51.9%, while the moisture content and crude fibre reduced by 21.3% and 23.8%, respectively.

Conclusion: The study showed that Aspergillus niger has the potential to reduce the theobromine content and enhance the nutritive value of cocoa by-products, for possible use in animal feed.