Open Access Original Research Article

Production and Characterization of Dextranase by Penicillium brevicompactum Isolated from Garden Soil

S. M. Wakil, O. J. Ibikunle, H. A. Akinyele

Journal of Advances in Microbiology, Page 1-12
DOI: 10.9734/JAMB/2018/45723

Aim: The aim of the study is to produce and characterize dextranase produced by fungi isolated from soil and honey.

Place and Duration of Study: The study was carried out at the Department of Microbiology, University of Ibadan, between April, 2017 and October, 2017.

Methodology: Garden soils were collected from different locations within the University of Ibadan, Nigeria, and filtered and unfiltered honey from a local honey farmer. Serially diluted soil and honey samples were pour-plated on PDA for isolation of fungi. Isolated fungi were screened, then on dextran containing medium to select dextranase producing strains.

Results: Forty two (42) fungi isolated from soil and honey was qualitatively and quantitatively screened for dextranolytic activity. Three moulds, Penicillium brevicompactum BG8, Fusarium oxysporum BG4 and Alternaria alternata DD5 were found to be the most potent dextranase producers with 18.01 DU/mL, 9.46 DU/ml and 8.26 DU/mL activities, respectively. Optimization of major parameters affecting enzyme production; including medium composition, pH, carbon (Temperature was not optimized at this stage) and nitrogen sources, substrate concentration revealed that maximum enzyme production was obtained when Pleszczynska medium was used for production. Penicillium brevicompactum BG8 and Alternaria alternata DD5 produced dextranase maximally at 1.0% dextran concentration with sodium nitrate and yeast extract as nitrogen sources at pH 5.5 at 30°C and 180 rpm for 5 days. Fusarium oxysporum BG4 produced dextranase maximally at 1.0% dextran concentration with sodium nitrate and yeast extract as nitrogen sources at pH 6.0 at 30°C and 180 rpm for 5 days. The production of dextranase by Penicillium brevicompactum, Fusarium oxysporum and Alternaria alternata increased to 65.41 DU/mL, 17.14 DU/mL and 20.10 DU/mL respectively when production was carried out using the best optimization conditions. Penicillium brevicompactum BG8 dextranase was purified to 14.1 fold homogeneity with an overall yield of 27% and an increase in specific activity from 2.67 – 37.68 U/g protein. Penicillium brevicompactum BG8 dextranase showed optimum activity at 50°C and pH 5.5, 2 mL substrate concentration and 1 ml enzyme concentration. Na+ ion activated dextranase while Cu2+ and Hg2+ ions completely inhibited the enzyme activity.

Conclusion: Soil and honey are potential sources of isolation of dextranase producing organisms, particularly in higher quantities which may probably provide a way out to cheap and commercially available enzyme.

Open Access Original Research Article

Studies on Microbial Succession Inhabiting the Phyllospheres of Local and Foreign Varieties of Sorghum bicolor

C. A. Ologunde, F. T. Akinruli, F. A. Ajayi

Journal of Advances in Microbiology, Page 1-8
DOI: 10.9734/JAMB/2018/45164

Aims: Sorghum bicolor has been identified as a prolific food producer, drought resistant and adapts well to other harsh environment. Its importance as a crop plant is being highlighted. This study investigates the isolation and succession of microorganisms inhabiting the phyllospheres (leaves, seeds, and stems) of four local varieties obtained from a market in Ado-Ekiti, Nigeria and two foreign varieties of sorghum obtained from Aberystwyth University, United Kingdom in order to scrutinize the disease-causing microorganisms that could inhabit the species of the plant and also to identify the varieties of sorghum that will adapt well to South West Nigerian soil.

Study Design: A piece of farmland with good soil was acquired from the management of Federal Polytechnic, Ado-Ekiti, Nigeria for plantation of sorghum.

Methodology: The six varieties of sorghum were planted and monitored for a succession of microorganisms on the leaves, stems, and seeds for 16 weeks.

Results: The fungal isolates include Aspergillus flavus, Aspergillus glaucus, Aspergillus niger, Fusarium spp., Mucor spp., Penicillium chrysogenium, Penicillium notatum, Penicillium oxalicum, Rhizopus spp., Syncephalastrum spp. and Butrysporium spp. The bacterial isolates were Staphylococcus aureus, Mycobacterium smegmatis, Pseudomonas syringae, Escherichia coli and Bacillus subtilis.

Discussion: The entire microorganisms were isolated from the local varieties except for Butrysporium spp. which was isolated from the foreign varieties. Some microorganisms were isolated early in the study but disappeared towards the end of the study. In the two foreign varieties of sorghum, the persistent bacterial isolates were Mycobacterium segmatis and Pseudomonas syringes while the fungal isolates were Rhizopus stolonifer, Mucor and Aspergillus flavus. In the four local varieties, the persistent bacterial isolates were Staphlococcus aureus and Bacillus subtilis while the persistent fungal isolates were Mucor, Aspergillus niger, Aspergillus flavus and Rhizopus stolonifer.

Conclusion: Irrespective of the microorganisms on the phyllospheres of both foreign and local varieties of sorghum, the plants thrived; therefore, sorghum can be planted to sustain food security in South West Nigeria.

Open Access Original Research Article

Detection of Aflatoxigenic Moulds and Aflatoxins in Maize and Millet's Grains Marketed in Zaria Metropolis

S. Shitu, D. A. Macchido, M. B. Tijjani

Journal of Advances in Microbiology, Page 1-9
DOI: 10.9734/JAMB/2018/40075

Aims: The present study was aimed at detecting of aflatoxigenic moulds and aflatoxins in maize and millet grains commonly marketed in Zaria Metropolis.

Study Design: The study was a laboratory-based research aimed at Detecting aflatoxigenic moulds and aflatoxins in the grains samples marketed in Zaria Metropolis

Place and Duration of Study: The samples were purchased from six different markets in Zaria metropolis between July and August 2016.

Methodology: Representative samples were subjected to proximate analysis and cultural isolation by grounding of each sample of (maize and millet) and separately added to 90 ml of sterile distilled water to form a stock suspension. An aliquot of 0.5 ml was spread on already prepared sweet potato yeast extract agar plate and the inoculated plates were incubated at room temperature. The suspected aflatoxigenic moulds were sub cultured and incubated at room temperature to obtain a pure culture and subjected to slide culture technique for microscopic identification of the moulds from the entire samples.  The main objective of this study was to detect aflatoxin-producing moulds in maize and millet grains commonly sold in Zaria metropolis markets. The isolates were then screened for aflatoxin production using desiccated coconut agar and viewed under UV light (365 nm). Enzyme-linked Immunosorbent Assay (ELISA) technique was used to determine total aflatoxin concentration of the samples.

Results: The results revealed that the maize (Zea) and millet samples analyzed contain organic and inorganic nutrients that can support the growth of aflatoxigenic moulds and production of aflatoxin. Sixteen (25) isolates from the 60 samples were contaminated which account for 41.7%. The percentage of   A. flavus isolates in maize was 26.7% and that of A. parasiticus was 15%.In maize, the occurrence of A. flavus was 23.3% and A. parasiticus 13.3% and the millet had 30% A. flavus and 16.7% A. parasiticus. The isolates demonstrated ability in aflatoxin production by emitting very bright fluorescent colouration under UV light (365nm). Total aflatoxin concentration in maize sample obtained from Samaru Market was found to be 18.10 µg/Kg while millets obtained from Zaria recorded 52.0 µg/Kg. The contamination levels within the grains were found to be statistically significant (p value< 0.05) using analysis of variance (ANOVA)

Conclusion: This study, therefore, revealed that the contamination level in millet samples analyzed calls for concern as it exceeded the standard limit set by NAFDAC and SON.

Open Access Original Research Article

The Use of Probiotic Containing Lactic Acid Bacteria to the Rescue of Antibiotics in Broiler Production

L. F. Ebu, A. A. Orukotan, J. R. Wartu

Journal of Advances in Microbiology, Page 1-10
DOI: 10.9734/JAMB/2018/45770

The research was aimed to study the effect of Lactobacillus fermentum, Lactobacillus plantenrun and Weissalla ciberia on growth performance, feed conversion ratio and mortality of broiler chicken. This was design to find a possible alternative to antibiotics in broiler production. The study was carried out at the Department of microbiology, faculty of sciences Kaduna State University, Kaduna between January to April 2018. A total of ten raw milk samples were screened for the isolation of Lactic Acid Bacteria (LAB) and twenty day-old broiler chicks (initial body weight 41 ± 0.5 g) were administered probiotics (Lactobacillus fermentum, Lactobacillus plantenrun and Weissalla ciberia) in water at 108 cells/milliliters/isolates/birds/day for six weeks. Body Weight (BW), Weight Gain (WG) and Feed Intake (FI) were measured weekly just as feed conversion ratio was calculated and mortality was recorded throughout the duration of the experiment. The results showed the identification of Lactobacillus fermentum, Lactobacillus plantenrun and Weissalla ciberia that were used as probiotics. Significant differences was observe between treatment on BW at day 14 P=0.0292 WG, P=0.0004 and FI P=0.0176, day 21 P=0.0329, WG P=0.0004 and FI P=0.0176, day 28 P=0.0025, WG P=0.0053 and FI P=0.0189, day 42 WG P=0.0112 and FI P=0.0006 and day 49 BW P=0.011, WG P=0.5289 and FI P=0.0006. Probiotics group showed a better body weight and weight gain with a lower feed intake and highest feed conversion ratio compared with antibiotic and control group. There was a progressive increase in weight gain from the first to the fourth but decreases from week five and six. The LAB group recorded 5%, mortality rate, antibiotics group recorded 10% and the control group recorded 0%. Probiotic lactic acid bacteria showed promising tendencies to replace antibiotics in broiler production as illustrated in this research work.

Open Access Original Research Article

Evaluation of the Fate of Saccharin during Storage of Sobo Drink

Kabir, B. Amina, A. A. Farouq, A. D. Ibrahim, A. U. Rabi’u, A. Bala, K. T. Mumuney, H. Salisu, S. Y. Abdullahi

Journal of Advances in Microbiology, Page 1-8
DOI: 10.9734/JAMB/2018/45704

Artificial sweeteners such as saccharin were used in place of sugar in the production of sobo drink. Sobo (Hibiscus sabdariffa) is a local drink produced by boiling the Sobo (Hibiscus sabdariffa), sieving out the calyces and addition of artificial sweetener such as saccharin Upon ingestion of the sobo drink, saccharin goes through the human digestive system where it is neither absorbed nor metabolised; it is excreted unmodified via the kidney. Samples were collected from Kasuwar Daji market in sokoto. The drinks were stored at room temperature and monitored for 21 days. The aim of this study is to evaluate the fate of saccharin during storage of sobo drink using microbial load and spectrophotometer. Bacteria load and type was determined using standard bacteriological analysis. The concentration of saccharin in the spoilt sobo drink was determined using spectrophotometer. GC-MS analysis was used for the identification and quantification of volatile compounds. The degradation process was found to mostly occur on the third day and the twelfth day of the storage, the degradation rate was found to be higher in lower concentrations of saccharin and lower in higher concentration of saccharin. The bacteria species isolated from the sobo drink, includes Bacillus subtilis, Bacillus pumilis, Bacillus azotomonas, Micrococcus varians, Aeromonas hydrophila, Enterobacter aeromonas, Lactobacillus acidophilus. This research shown that prolonged storage results in the predominance of common spoilage bacteria and  coliform bacteria  in the sobo drink and were found to be capable of degrading saccharin which results in the formation of 2-sulfano benzamide as the degradation product.

Open Access Original Research Article

Microbiological Indoor Quality Assessment of Public Toilets in Port Harcourt Metropolis, Rivers State, Nigeria

S. I. Douglas, J. A. Lumati

Journal of Advances in Microbiology, Page 1-7
DOI: 10.9734/JAMB/2018/45716

Aims: Assessing the microbiological quality of indoor air in some public toilets of major motor parks in Port Harcourt metropolis

Study Design: Indoor air of public toilets in three major parks in Port Harcourt was sampled using the sedimentation technique. This was done in two periods (morning and evening).

Place and Duration of Study: This study, were carried out in the Mile 3, Waterlines and RTC motor parks public toilets. This was a three months study (March-May, 2018).

Methodology: The sedimentation technique was used in evaluating for microbial population of air samples. Freshly prepared Nutrient (NA), MacConkey and Sabouraud Dextrose agar (SDA) plates in duplicates were left open for 15minutes and 1m above the ground in the various study sites. Samples were later transported to the Microbiology Laboratory and incubated at 28ºC for 3-7 days for fungi and at 37ºC for 24 hours for bacteria and coliforms. After incubation, bacterial and fungal populations were enumerated and distinct isolates were purified by subculturing onto fresh NA and SDA plates. The purified isolates were used for characterization.

Results: Bacterial genera belonging to; Staphylococcus, Bacillus, Providencia, Pseudomonas, Escherichia, Enterobacter and Klebsiella were isolated and fungal genera belonging to:  Aspergillus, Penicillium, Rhizopus, Candida, and Mucor species were identified in this study.

Conclusion: The high microbial loads in this study indicate that the indoor airs of these public toilets were above the suggested WHO standard of 1000Cfu/m3. Thus, this could pose serious health challenges to people who use and even those who work in the public toilets. Also, some of the bacterial and fungal genera identified could be pathogenic strains which may cause diseases or other allergic reactions.

Open Access Original Research Article

Antibiotic Susceptibility Profile of Gram-negative Enterobacteriaceae from Women Attending Selected Hospitals in Sokoto, North Western Nigeria

Maimuna Attahiru, Nuhu Tanko

Journal of Advances in Microbiology, Page 1-5
DOI: 10.9734/JAMB/2018/45968

Aims: The aim of our study is to isolate, characterize as well as determine the antibiotic susceptibility pattern of Gram-negative Enterobacteriaceae from women attending some selected hospitals in Sokoto, North western Nigeria.

Study Design: The study was designed to isolate and characterize Gram-negative organisms isolated from women attending some selected hospitals in Sokoto state. Only women of age 18 years and above were included. Each of the participants gave a written and verbal consent of their willingness to participate in the study.

Place and Duration of Study: The study was conducted in a tertiary specialist hospital and 3 other secondary health facilities within Sokoto metropolis for a period of 5 months (March to August, 2018).

Methodology: Urine samples were inoculated on prepared CLED agar. Samples count up to and greater than 106cfu/ml were considered positive. Microgen GN-ID was used to identify the bacterial isolates based on manufacturer’s instruction. Antibiotic susceptibility testing was determined against 8 antibiotics using the modified Kirby-Bauer disc diffusion method on Mueller Hinton agar. Results of AST were interpreted using the CLSI guideline.

Results: A total of 411 urine samples were analyzed during the period. Out of the 411 samples, 73 (17.8%) were Gram negative isolates. The AST showed that the Gram-negative isolates were highly sensitive to piperacillin/tazobactam (100.0%), followed by imipenem (98.1%), then ciprofloxacin (93.1%). norfloxacin showed 72.6% sensitivity, while gentamicin and nalidixic acid showed sensitivity of 68.5% and 56.2% respectively. Majority of the isolates were resistant to ampicillin and co-trimoxazole.

Conclusion: E. coli was the most prevalent among the uropathogens investigated. The high resistance encountered with co-trimoxazole and ampicillin underscores the need for continuous monitoring of antibiotic susceptibility result before the commencement of treatment. This can be complimented with antibiotic stewardship if possible in these hospitals.

Open Access Original Research Article

Microbiological Quality, Proximate Composition and Heavy Metal Contamination of Pond-raised Catfish (Clarias gariepinus)

P. T. Fowoyo, M. E. Isaac

Journal of Advances in Microbiology, Page 1-10
DOI: 10.9734/JAMB/2018/45598

Catfish (Clarias gariepinus) is a commonly consumed fish in Nigeria. Its high demand necessitated fish farming in ponds which is now the current trend for fish production in Nigeria. Thus, the safety and quality of pond raised catfish has to be ascertained. The nutritional content, microbiological quality and heavy metal contamination of twenty (20) pond-raised catfish purchased from four different markets in Lokoja, Nigeria was determined using standard laboratory methods. The total bacterial count ranged between 1.5 x 103 - 3.9 x 103 cfu/g while the total fungal count ranged between 1.0 x 103 - 2.2 x103 cfu/g from the different sampling locations. The fungi from the pond raised fish samples were identified as Rhizopus stolonifer, Aspergillus niger, Mucor sp., Penicillum sp. and Fusarium sp. The bacterial isolates were identified as Escherichia coli, Micrococcus sp., Salmonella sp., Staphylococcus aureus, Proteus sp., Bacillus sp., and Pseudomonas sp. Iron (Fe), copper (Cu), nickel (Ni), zinc (Zn) were present in all the fishes examined at concentrations not exceeding the approved permissible limits in food although lead (Pb), and cadmium (Cd) were below detection limits in all the fish samples. Pond raised catfish is a rich source of protein and fat. The incidence of some likely enteric and toxigenic organisms in the fish calls for a systematic approach in ensuring safety of the consumers. The consumption of the fish does not pose a likely source of heavy metal accumulation however the source of zinc in the fish should be identified as they can bio-accumulate quickly and pose a serious health risk to man.

Open Access Original Research Article

Optimization of Invertase from Aspergillus niger Grown on Low Cost Agricultural Wastes by Response Surface Methodology (RSM)

Francis Sopuruchukwu Ire, Vitalis Junior Aguguo, Victor Ezebuiro

Journal of Advances in Microbiology, Page 1-15
DOI: 10.9734/JAMB/2018/45480

Aim: To optimize media components and cultural conditions using response surface methodology (RSM) in the production of invertase by Aspergillus niger grown on potato peels (P1) and pineapple peels (P2).

Place and Duration of Study: The study was conducted at Environmental Microbiology laboratory, University of Port Harcourt, Choba between September 2015 and January 2017.

Methodology: Chemical analyses of P1 and P2 were carried out using standard methods. Invertase production was screened using Fehling solution test coupled with invertase activity assay. Reducing sugar was estimated using dinitrosalicylic acid (DNS) procedure. The RSM optimization design involved four (4) independent variables (pH, temperature, pineapple peels concentrations, and potatoes peels concentrations) at five (5) levels, screened through thirty (30) different experimental runs using central composite design (CCD).

Results: Optimal fermentation conditions that yielded maximum invertase (321.4 U/mL) and biomass (11.34 mg/mL) by A. niger was achieved with the combination of pH 9.0, temperature 35°C, pineapple peels concentration 10%, and potato peels concentration 50%. The model used gave a predicted R-Squared of -0.2258. Negative "Predicted R-squared” implies that the overall mean may be a better predictor of the response than the current model. "Adequate precision" of 6.190 was obtained, showing that the model can be used to navigate the design space.

Conclusion: This result has demonstrated the efficiency of RSM technique to optimize invertase production from A. niger using potato and pineapple peels as substrates. The use of local substrates can make invertase production economically attractive.

Open Access Review Article

A General Outlook on Methicillin Resistant Staphylococcus aureus

Belgin Siriken, Gökhan Inat, Alper Çiftci

Journal of Advances in Microbiology, Page 1-12
DOI: 10.9734/JAMB/2018/44856

Methicillin resistant Staphylococcus aureus (MRSA) is a kind of bacteria which is resistant against methicillin and other kind of many antibiotics. S. aureus and MRSA can lead to serious problem in human as well as animals. The problem can be simple or sometimes serious such as skin infections, sepsis, pneumonia and bloodstream infections. Firstly, MRSA was largely related to hospital-acquired (HA) infection. However, it is well understood that there is other source of MRSA.  Nowadays, MRSA has been divided three group; (1) Hospital-Associated MRSA (HA-MRSA), (2) Community-Acquired MRSA (CA-MRSA) and (3) Livestock-Associated MRSA (LA-MRSA). In addition to the three groups, MRSA has been found variety of animal origin foods (beef, poultry and pig meats and milk like that). Therefore, food of animal origin can contaminate with MRSA bacteria, and it can spread to human and animal through food chains. MR (methicillin resistance) in S. aureus is primarily mediated by overproduction of the penicillin-binding protein (PBP) 2a, and altered PBP with extremely low affinities for ß-lactam antibiotics. The mecA gene encodes a PBP2a form that is absent in susceptible isolates. The importance of MRSA; (i) MRSA can acquire resistance against many antibiotics more easily than other microorganisms, (ii) it acquires resistance to one antibiotics and to go into antibiotic groups, (iii) the Panton-Valentine leucocidin (PVL) toxin is a cytotoxin causing leukocyte destruction and necrosis of tissue. It is very important a virulent factor and produced by Staphylococcus aureus. The toxin is very common in especially CA-MRSA strains, and these strains are commonly considered far more likely to carry the gene coding for the toxin than are other MRSA strains, and (iv) MRSA infections require long-term inpatient cure and have a high rate of mortality.  For these reasons, today, MRSA is among the most important causes of antimicrobial-resistant health care-related to infections across the world.