Open Access Original Research Article

The Potential Use of Ectoine Produced by a Moderately Halophilic Bacteria Chromohalobacter salexigens KT989776 for Enhancing Germination and Primary Seedling of Flax “Linum usitatissimum L.” under Salinity Conditions

Tamer A. Elsakhawy, Nashwa, A. H. Fetyan, Azza A. Ghazi

Biotechnology Journal International, Page 1-12
DOI: 10.9734/bji/2019/v23i330078

The similarity between plant and microbial cells encourage the use of microbial metabolites of halophilic bacteria for the alleviation of salt stress in plants. In the current research work, a compatible solute ectoine extracted from a moderately halophilic bacteria Chromohalobacter salexigens KT989776 was used to enhance flax germination and primary seedling under different levels of salinity. Two successive experiments including germination in Petri plates under six levels of salinity (0, 3, 5, 7, 9 and 11 dS.m-1) and a pot experiment under three irrigating water salinity levels (2, 3 and 4) with two types of ectoine application (spray and soil addition) were conducted. Germination parameters were recorded for the first experiment while a fresh and dry weight of plants and peroxidase activity in addition to sodium-potassium ratio were estimated in the pot experiment. Also, ectoine accumulation in plants was detected using HPLC. Results of LC-MS proved the production of ectoine by C. salexigens KT989776 and ectoine enhanced significantly all germination parameters of flax seeds, decreased sodium accumulation in the plant, increased potassium content, and lowered peroxidase and phenoloxidase activity. Also, HPLC analysis proved that ectoine was detected in all treated samples while not detected in non-treated control.

Open Access Original Research Article

Effect of Cultural Conditions on Biosurfactant Production by Candida sp. Isolated from the Sap of Elaeis guineensis

I. V. Nwaguma, C. B. Chikere, G. C. Okpokwasili

Biotechnology Journal International, Page 1-14
DOI: 10.9734/bji/2019/v23i330079

Aims: This study is aimed at determining the effect of cultural condition on biosurfactant production by Candida sp. isolates from saps of Elaeis guineensis.

Methodology: Chemical analysis of the sap was carried out. Yeast isolates from the sap were screened for biosurfactant production based on emulsification index (E24), emulsification assay, haemolytic assay, oil displacement test, CTAB and tilted glass slide ability. The best biosurfactant-producing yeast isolate was identified based on its phenotypic, microscopic, and biochemical characteristics. The emulsification capacity of the produced biosurfactant on selected oils was studied. Optimum cultural and nutritional requirements (temperature, pH, inoculum       concentration, nitrogen sources and carbon sources) for biosurfactant production by the isolate were determined.

Results: The characteristics of the sap from Elaeis guineensis were reducing sugar (0.51 ± 0.03 mg/ml), alcohol (14.04 ± 0.15%), specific gravity (0.827±0.024), and pH (5.68±0.03). The crude biosurfactant produced displaced a thin film of crude oil on petri dish by 55 mm, and revealed high emulsification index (E24) of 52.5% using Olive oil as substrate compared to E24 of 60.6% by sodium dodecyl sulphate (SDS). Based on colonial, microscopic, and biochemical characteristics, the isolate SA2 was identified as Candida sp. The crude biosurfactant showed varying capacity in emulsifying the different oils that were examined. Optimization data revealed maximum biosurfactant production after 7 days of incubation, inoculum concentration of 10%, at temperature of 20ºC, pH of 2 with cassava peel as substrate.

Conclusion: The study has demonstrated the capacity of Candida sp. from the sap of Elaeis guineensis to produce biosurfactant utilizing cassava peel as substrate. The use of cassava peel, which represents a low-cost substrate, is important in reducing the cost of biosurfactant production. Moreover, using yeasts from Elaeis guineensis make the production process ecologically friendly.

Open Access Original Research Article

Diversity and Phylogenetic Relationships of Full Genome Sequences of Cassava Brown Streak Viruses in Kenya

T. M. Kathurima, E. M. Ateka

Biotechnology Journal International, Page 1-11
DOI: 10.9734/bji/2019/v23i330080

Cassava brown streak disease is caused by cassava brown streak virus (CBSV) and Uganda cassava brown streak virus (UCBSV). Many of the CBSV and UCBSV diversity studies utilize partial coat protein sequences due to the unavailability of representative full genome sequences. Hence, there is little information on the diversity of cassava brown streak viruses in the rest of the genomes of the two species that are present in the farmers’ fields. The aim of this study was to determine Kenyan full CBSV and UCBSV genomes, and their sequence diversity and phylogenetic relationships within various genome and genome segments. Twenty four CBSVs positive samples tested by RT PCR from major cassava producing regions in Kenya were sequenced using Illumina MiSeq. Quality assessment of the output reads was done using the CLC Genomics 5.5.1 software programs. Genome assembly was done by de novo and reference guided assembly. Nucleotide sequence similarity of CBSV and UCBSV was determined. Phylogenetic relationships between CBSV and UCBSV were determined by performing the neighbour-joining analysis using MEGA 6.0 software. Six CBSV and 9 UCBSV genomes were generated from this study. The coat protein of the CBSV sequences had nucleotide sequence similarity of 92-100% while P1 and P3 gene had 75-100% and 76-100%, respectively. The coat protein of the UCBSV sequences had nucleotide sequence similarity of 91-99%. P1 and P3 gene had 83-100% and 86-99%, respectively. The phylogenetic analysis of full genomes revealed two distinct clusters one for UCBSV and another cluster for CBSV. Individual gene segments phylogenetic tree resembled that of the whole genome by clustering the nucleotide sequences into two clusters, one belonging to UCBSV and the other CBSV. The study revealed an average genome nucleotide diversity of 21.5% and 15.8% in CBSV and UCBSV respectively. A vast genetic diversity observed in CBSV and UCBSV in this study portends a lot of challenges in developing molecular diagnostic techniques as well as control strategies against the viruses.

Open Access Original Research Article

Evaluation of Antimicrobial Activities of Fractions of Plant Parts of Pterocarpus santalinoides

S. C. Emencheta, I. B. Enweani, A. N. Oli, U. M. Okezie, A. A. Attama

Biotechnology Journal International, Page 1-11
DOI: 10.9734/bji/2019/v23i330081

Aims: The study aims to investigate the antimicrobial activities of the leaves, seeds, bark, and root of Pterocarpus santalinoides plant.

Study Design: Agar well diffusion and Agar well dilution methods were used to test the preliminary antimicrobial and minimum inhibitory/bactericidal/fungicidal concentrations respectively of Pterocarpus santalinoides plants.

Place and Duration of Study: Department of Pharmaceutical Microbiology and Biotechnology, Faculty of Pharmaceutical Sciences, Nnamdi Azikiwe University, Agulu Campus, Nigeria, between February – October, 2017.

Methodology: Primary extraction and fractionation of the plant parts were undertaken with methanol, butanol, ethyl acetate, and n-hexane. Agar diffusion method for the primary antimicrobial screening on Muller-Hinton agar (bacteria) and Sabouraud dextrose agar (fungi) were used to assess the antimicrobial activities of the sixteen (16) samples on some microbial isolates namely Salmonella typhi, Escherichia coli, Candida albicans, Aspergillus niger, Microsporon canis, and Trichophyton rubrum. The minimum Inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC) and percentage inhibition diameter growth (PIDG) of the samples that yielded positive activity were also evaluated.

Results: Twelve (12) samples exhibited inhibitory activity on at least one or more of the test isolates. The MIC range observed for the extracts and fractions that yielded positive activity was 12.5 – 100 mg/ml. The n-hexane fraction of the plant root indicated the best value of 12.5 mg/ml against M. canis. The best MBC/MFC value of 25 mg/ml was observed with the ethyl acetate fraction of the bark (against E. coli and M. canis) and the n-hexane fraction of the root (against M. canis). The result showed S. typhi to be the most sensitive organism to the metabolites of P. santalinoides. Extended-spectrum activity was observed with the ethyl acetate fraction of the bark against three (3) of the test isolates namely S. typhi, E. coli and M. canis. The determination of PIDG values for the test organisms against the plants’ extracts/fractions showed that crude methanol extract (28.57%) and ethyl-acetate fraction (0.14%) of the leaves, butanol fraction (0.14%) of the root (all against S. typhi) were the most potent test samples.

Conclusion: The results indicated that the plant parts may have potential medicinal values and confirmed its use in traditional medicine.

Open Access Original Research Article

Callus Induction and Synthetic Seed Development in Draceana sanderiana Sanderex Mast: Lucky Bamboo

Mohmad Amin, Abdul Mujeeb

Biotechnology Journal International, Page 1-8
DOI: 10.9734/bji/2019/v23i330082

The study was carried out for callus induction and synthetic seed development from the shoot tips of Draceana sanderiana sander ex Mast. The shoot tips were subjected to different concentrations (0.25, 0.5 &1.0 mg/l) of 2,4-D on MS medium. The research findings revealed that the 2,4-D at concentrations of 0.25 mg/l was more suited for the profuse callus formation. The friable and light yellow callus was induced within 2 weeks of culture at 0.25 mg/l of 2,4-D on MS medium as compared to the other two concentrations of 2,4-D i.e.; 0.5 and 1.0 mg/l. Similarly the effect of sodium alginate and calcium chloride percentage on synthetic seed formation was observed, it was found that somatic embryos formed from shoot tips via callus kept in 2.5% sodium alginate and 100 milli molar CaCl2 produced synthetic seeds with firm spherical beads. The study leads to the formation of synthetic seeds of Draceana sanderiana which can be used for the conservation of germplasm through cryopreservation and the micro propagation of the said plant species.