Open Access Minireview Article

Soil Bioremediation in Heavy Metal Contaminated Mining Areas: A Microbiological/Biotechnological Point of View

Jéssica Dutra Vieira, Valdir Marcos Stefenon

Journal of Advances in Microbiology, Page 1-10
DOI: 10.9734/JAMB/2017/33782

Bioremediation concerns the use of plants and microorganisms or their parts, for the decontamination and recuperation of polluted areas. The improvement of the bioremediation techniques is possible due to the last decade advances of the microbiological and biotechnological knowledge and methods. This study aimed to shortly review and discuss the bioremediation of mining areas contaminated with heavy metals focusing in some microbiological and biotechnological techniques. Strategies considered to be important on further studies are also presented.

 

Open Access Original Research Article

Fungal Contamination of Locally Processed Nigerian Food (Okpa): A Threat to Public Health

P. T. Nnaji, A. P. Rao

Journal of Advances in Microbiology, Page 1-8
DOI: 10.9734/JAMB/2017/33007

Aim: The aim of this study is to determine the level of contamination associated with locally processed Vignea subterranea (okpa) flour in Nigeria.

Study Design: The completely randomized experimental design was adopted for this study.

Place and Duration of Study: The staff laboratory in University of Calabar Cross River State Nigeria was used for this research, within the space of two months.

Methodology: Standard microbiological research methods were adopted for the culture, isolation and identification of fungi. Spore heads and hyphae growth were compared with standard mycological atlas.

Results: Locally processed Vigna subterranea from South Eastern Nigeria markets and mills were analyzed for level of fungal contamination. Aspergillus niger, Trychophyton spp, Penicillium spp, Rhizopus nigrican, Chrysosporium spp, Geotrichum spp, Mucor spp and Syncephalastrum spp were identified at a percentage occurrence of 20.6, 5.6, 17.7, 20.6, 8.8, 2.9, 20.6 and 2.9 respectively. The Mean (x) percentage growth of fungal species was 12.46, a standard deviation (δ) of 8.19 and Variance (S.D)² of 67.08.

Conclusion: Locally processed V. subterranea in Nigeria can pose harm to the consumers of the food due to poor hygienic practice, unethical conduct and production inefficiency by food processors and handlers. Deliberate efforts must be made to curb the chances of contamination by microorganism especially fungi that may likely pose some level of resistance to heat.

 

Open Access Original Research Article

Comparative Study of Phytochemical Constituents and Antimicrobial Activities of Acalypha wilkesiana and Acalypha godseffiana Extracts

A. O. Aladejimokun, K. M. Daramola, O. J. Osabiya, O. C. Arije

Journal of Advances in Microbiology, Page 1-7
DOI: 10.9734/JAMB/2017/32999

Aim: The aim of the investigation was to evaluate and compare the phytoconstituents and antimicrobial activities of leaf extracts of two species of Acalypha (A. wilkesiana and                      A. godseffiana).

Methodology: The methods employed include manual pulverization of the air-dried leaves and solvent (ethanol) percolation for 72 hrs. The crude extracts were kept in sterile Mc Cartney bottles and stored in the refrigerator 4±2°C. Thereafter, they were screened for phytochemical components. Moreover, they were investigated for antimicrobial activities against Bacillus subtilis, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Streptococcus pneumoniae, Staphylococcus aureus, Aspergillus flavus, Candida albicans, and Cryptococcus neoformans.

Results: From the results obtained during the study, flavonoid, saponin, phobatanin, tannin and alkaloid were found in both A. wilkesiana and A. godseffiana, steroid was found only in                          A. wilkesiana while terpenoid and anthraquinones were not detected in the two species. The quantitative screening showed that A. wilkesiana extract possess more of flavonoid (7.32 µg/g), tannin (4.21 µg/g), alkaloid (4.19 µg/g) and steroids (1.18 µg/g) compared to the extract of A. godseffiana, whereas, saponin (5.23 µg/g) and phobatanin (4.32 µg/g) were found to be present in higher quantities in A. godseffiana than the extract of A. wilkesiana. The antimicrobial activity assay revealed that at the highest concentration used (50 mg/ml) the zones of inhibition ranged from 9.00±0.00b mm against A. fumigatus to 16.00±0.00d mm against S. aureus. Moreover, there was a significant difference between the susceptibility of Gram positive bacteria and Gram negative bacteria. The extract of A. godseffiana was more active against the selected pathogens compared to the extract from A. wilkesiana.

Conclusion: The results obtained suggest that both species of Acalypha possess comparable phytochemicals however, A. godseffiana was more potent as antimicrobial agent than A. wilkesiana this support their folkloric use as remedy for several disease conditions and new antimicrobial agents may be developed from them.

 

Open Access Original Research Article

Bioefficacy Test of Different Chemotherapeutic Substances against Aspergillus sp. and Chrysosporium sp. Contaminants of Tissue-Cultured Abaca (Musa textiles NEE.) during Initial Stage of Micropropagation

Jojine S. Cobrado, Alminda M. Fernandez

Journal of Advances in Microbiology, Page 1-12
DOI: 10.9734/JAMB/2017/33289

The study was conducted at the Tissue Culture Laboratory and Crop Research Laboratory of the University of Southeastern Philippines to test the efficacy of selected antibiotics and antifungal agents in the elimination of the common fungi contaminant of tissue-cultured abaca meriplants during initial stage of propagation on the Murashige and Skoog medium.

Microbial symptoms were observed based on their colony shape, colony margin/ elevation and colony color in 20 bottle test media during one month (Initial stage) observation period. The technique of James and Natalie was adopted for identification of the unknown isolated fungi. The species encountered were identified and characterized following the technique of James and Natalie. The Poisoned Food Technique for Antibiotic Sensitivity Testing for Fungi was used. The experiment was laid-out in completely randomized design (CRD) with five treatments replicated three times. There were five plates per replicate for a total of 75 plates. The treatments were: T1-Control (No treatment); T2-Streptomycin (200 mg·L-1); T3-Nystatin (1 ml·L-1); T4-Streptomycin (200 mg·L-1) + Nystatin (1 ml·L-1); and T5-Benomyl (Chemical check, 100 mg·L-1).

Study showed that the common contaminants of tissue-cultured abaca were fungal colonies such as Aspergillus sp. and Chrysosporium sp. like fungus appeared on the 10th day and 12th day after initiation, respectively with a total of 15% rate of occurrence.

Result of in vitro test likewise showed that T5 - Benomyl (Chemical check, 100 mg·L-1) significantly inhibited the growth of Aspergillus sp. T3 - Nystatin (1 ml·L-1) also inhibited the growth of fungal contaminants same as Chrysosporium sp. These fungal species were found to cause death of the culture biological material by some probable sources of contaminations, such as handling of plant materials, culture vessels and the laboratory. The result of the study suggests that both Benomyl (Chemical check, 100 mg*L-1) and Nystatin (1 ml*L-1) can be used to inhibit growth of fungal contaminants, such as Aspergillus sp. and Chrysosporium sp. like fungus.

 

Open Access Original Research Article

Preliminary Investigation of Bio-preservative Effect of Cola millenii Extracts on the Shell-Life of “Kunu-Zaki”

B. L. Adewumi, O. C. Arije

Journal of Advances in Microbiology, Page 1-11
DOI: 10.9734/JAMB/2017/33518

Aim: The aim of this study was to investigate the potentials of Cola millenii seed and pulp extracts as a possible bio-preservative agent for kunu-zaki, a Nigerian fermented beverage.

Methodology: The plant materials were grinded mechanically and macerated in solvent (acetone and ethanol) for 72 hrs. Kunu-zaki was produced using traditional procedures and the reconstituted extracts were aseptically introduced into it. Thereafter, the samples were stored at room temperature and in the refrigerator for 15 days.

Results: The pH and total titrable acidity of the freshly produced kunu-zaki were 4.49±0.01 and 0.38±0.00 respectively. The total heterophilic bacterial count of the freshly produced kunu-zaki was 5.6 X 102 cfu/ml, total fungal count was 2.7 X 102 cfu/ml while the lactic acid bacterial count was 11.1 X 102 cfu/ml. Moreover, seven bacteria and six fungi were isolated from the freshly prepared kunu-zaki, they were Pseudomonas aeruginosa, Bacillus subtilis, Bacillus licheniformis, Micrococcus luteus, Lactobacillus acidophilus, Lactobacillus plantarum, Streptococcus species, Geotrichum candidum, Saccharomyces cerevisiae, Aspergillus niger, Rhizopus stolonifer, Fusarium species and Penicillum species. The seed and pulp extracts of C. millenii reduced the bacterial load in the kunu-zaki compared with the controls, and C. millenii pulp extracted with ethanol (PEE) totally suppressed microbial growth in kunu-zaki from day 10 onward. C. millenii pulp extracted with acetone (PAE) and PEE had the best scores for aroma from day 7 to day 15 of storage while PAE, PEE and kunu-zaki without preservative stored in the refrigerator (FRG) had a significantly higher rating for taste throughout the storage period. The overall acceptability of the bio-preserved products as well as the controls was not significantly different (p≤0.05) during the first three days and tenth day of storage.

Conclusion: From the foregoing, there is great amount of evidence suggesting that the ethanol extract of Cola millenii pulp possess bio-preservative potentials against kunu-zaki spoilage. Therefore, it may be expediently exploited in the food and beverage industries to extend the shelf-life of their products.