Open Access Original Research Article

Screening of Bacteriocin Production in Lactic Acid Bacteria Isolated From Fermented Dairy Products

Esra Demir, Gamze Başbülbül

Biotechnology Journal International, Page 1-9
DOI: 10.9734/BJI/2017/33504

Aims: In this study we aimed to screen LAB strains from different fermented dairy products by phenotypic and genotypic methods.

Methodology: 138 LAB isolates belonging to Enterococcus (13,76%), Lactococcus (18,84%) and Lactobacillus (67,39%) genera from fermented dairy products were used to search for their bacteriocin production and  bacteriocin encoding genes were searched. LAB isolates were screened by spot-on lawn assay method against indicator microorganisms. Geobacillus stearothermophilus DSMZ 22, Escherichia coli ATCC 35218, Bacillus cereus, Listeria innocua, Listeria monocytogenes, Enterococcus faecalis, Micrococcus luteus, Lactococcus lactis DSMZ 20729 and Lactobacillus plantarum DSMZ 20205. Cell-free supernatants (CFS) of LABs  used for agar-well diffusion assay to confirm antibacterial activity.

Results: All the LAB strains exhibited antibacterial activity against indicator bacteria at varying degrees by spot on lawn method. None of the CFS except one belong to positive control Lactococcus lactis DSMZ 20729 showed inhibitory effect by agar well diffusion assay. According to PCR results which used to investigate the bacteriocin genes of LAB’s , ent-A (5,07%), ent-B (2,17%), lcn-A (2,17%), and pln (1,44%) genes were detected in some of the isolates.

Open Access Original Research Article

Optimization of Lipase Production by Bacillus megaterium

Fadahunsi Ilesanmi Festus, Akoh Queen Phebe

Biotechnology Journal International, Page 1-11
DOI: 10.9734/BJI/2017/32505

Aim:  To optimize lipase production by Bacillus megaterium in submerged fermentation.

Study Design: Collection of palm oil press fibres and effluent from different palm oil mills located within Ibadan Municipality. Isolation of Bacillus megaterium by cultivation in medium, submerged fermentation of palm oil press fibres and effluent by B. megaterium to produce lipase. Alteration of the cultural conditions to optimize production.

Place and Duration of Study: All work were done in the Department of Microbiology, Faculty of Science, University of Ibadan, from January–December 2014.

Methodology: Palm oil press fibres and effluent were collected from various palm oil mills and were used as the source of isolation of microorganism. The isolated species were identified by studying the morphological, biochemical, characteristics and 16SrNA gene sequencing. The selected species was screened for lipase production.

Results: The results obtained revealed that maximum lipase production was recorded at pH 7.0 with an activity 2.13±0.15 U/ml while the best temperature that supported the optimum production of lipase was seen at 35°C with an activity of 3.30±0.10 U/ml and the best carbon and nitrogen sources were 2% glucose and 2.5% peptone concentrations showing activities of 1.83±0.05 U/ml and 2.60±0.10 U/ml respectively. An incubation period of 72 hours produced the optimum lipase with an activity of 3.26±0.05 U/ml. The separate additions of 0.3M Ca2+ and 0.3M Cl- supported maximum production of lipase.

Conclusion: This study showed that lipase production by B. megaterium can be optimized and the best conditions for optimization included pH 7.0, temperature of 35°C, 72 hours incubation period in the presence of 2% glucose, 2.5% peptone concentrations and 0.3M Ca2+ and 0.3M Cl-.

Open Access Original Research Article

Use of the Internal Transcribed Spacer (ITS) Regions to Characterize Macaw Progenies

Flavia Campos Vieira, Marcelo Luiz de Laia, Ariadne Marques, Janaína Fernandes Gonçalves, Ronnie Von dos Santos Veloso

Biotechnology Journal International, Page 1-8
DOI: 10.9734/BJI/2017/32718

Aims: The present study aimed to investigate the genetic structure of A. aculeata (macaw palm) groups by analyzing individual polymorphism of different ITS regions.

Study Design: Experimental design study.

Place and Duration of Study: Department of Forest Engineering (Universidade Federal dos Vales do Jequitinhonha e Mucuri/MG) and Germoplasm Bank of macaw (Universidade Federal de Viçosa/MG), between February 2014 and December 2015.

Methodology: DNA extracted from 42 leaf samples of Macaw palm. Five universal oligonucleotide primer pairs specific for different internal transcribed spacer (ITS) regions of nuclear ribosomal DNA of Macaw (ITS 1, ITS 2, ITS 3, ITS 4, and ITS 5) used for PCR amplification.

Results: Of 42 analyzed samples, 20 resulted in reproducible bands for primers ITS 1 and ITS 2, 21 for ITS 3 and ITS 4, 24 for ITS 2 and ITS 5, and 22 for ITS 4 and ITS 5. Samples were grouped based on these results.

Conclusion: Therefore, it was possible to identify genetic differences among Macaw progenies based on the quality of ITS sequences.

Open Access Original Research Article

In vitro Propagation of Oxytenanthera abyssinica (A. Rich. Munro) from Seed Culture

Birhanu Kahsay, Firew Mekibib, Adefris Teklewold

Biotechnology Journal International, Page 1-13
DOI: 10.9734/BJI/2017/32715

Introduction: In Ethiopia, O. abyssinica has varies economic importance. However, conventional propagation methods of O. abyssinica are generally inefficient due to their low multiplication rate, time consuming, labor intensive, and too costly.

Aims: The objective of this study was to develop a protocol for micropropagation of O. abyssinica through seed culture.

Methodology: For seed disinfection, NaOCl of 3, 4, and 5% concentration for 15, 20, and 25 min exposure time were tested. MS medium augmented with BAP or KN at different concentrations was used for shoot initiation and multiplication. For in vitro rooting, ½MS medium supplemented with IBA or NAA at different concentrations was used. Data were subjected to ANOVA and mean values were compared using LSD at a 5% of probability level.

Results: Seeds disinfected in 4.0% NaOCl for 25 minutes gave 71.6% clean explants and 23.45% germinated explants. In shoot initiation experiment all viable seeds were able to proliferate in 5-7 days of culturing in all treatments; and 4.0 mg dm^-3 BAP was found better in maximum shoot initiation percent (86.67) and mean number of shoots per explants (4.8). Similarly, in shoot multiplication 4.0 mg dm^-3 BAP was effective in highest mean number of shoot (11.33) and multiplication rate (3.77). The maximum rooting percent (93.33) and maximum root number per clump (9.42) were found at 8.0 mg dm^-3 IBA. Finally, the survival rate of plantlets in greenhouse condition was found to be 91.67% after 30 days of acclimatization.

Conclusion: The study enables to develop an effective and applicable protocol for O. abyssinica micropropagtion.

Open Access Original Research Article

Antibacterial and Hemagglutinating Activity of the Fruit Pulp of Trilepisium madagascariense DC

Oludele O. Odekanyin, Temitope T. Aibinu, Olutayo Abioye

Biotechnology Journal International, Page 1-9
DOI: 10.9734/BJI/2017/31313

Aim: This study aimed at exploring the hemagglutinating and antibacterial activities of crude lectin from the fruit pulp of Trilepisium madagascariense DC.

Methods: Crude lectin was obtained by maceration of the fruit and ammonium sulphate precipitation. Hemagglutinating activity assay was carried out by determining the ability of the crude extract to agglutinate red blood cells, serial dilution of the crude lectin was done followed by addition of erythrocytes. The crude lectin was subjected to evaluation for inhibition of bacterial growth by the agar well diffusion method against fourteen human pathogenic gram-positive and gram-negative bacteria.

Results: The extract agglutinated trypsinized and glutaraldehyde-fixed rabbit and human erythrocytes with higher specificity for rabbit erythrocytes and better agglutination with trypsinized erythrocytes. Among the various sugar tested, the hemagglutination was best inhibited by galactose. The crude lectin demonstrated mild spectrum antibacterial activity against four pathogenic gram-positive and gram-negative bacteria. The minimum inhibitory concentration ranged from 1.56 mg/ml to 6.25 mg/ml for Streptococcus faecalis, Bacillus anthracis, Staphylococcus aureus and Pseudomonas fluorescens.

Conclusion: The study showed that there is presence of hemagglutinins in the extract  and the extract possess antibacterial potential against some pathogenic bacteria tested and can be developed as alternative antibacterial drug that could be employed for the treatment of infectious diseases caused by these pathogens.