Open Access Original Research Article

Antimicrobial Activity and Toxicity of Sophorolipids Produced by Candida haemulonis and Saccharomyces cerevisiae against Some Selected Microorganisms

K. F. Williams, O. K. Agwa, G. O. Abu, O. Akaranta

Journal of Advances in Biology & Biotechnology, Page 1-9
DOI: 10.9734/jabb/2021/v24i930234

Sophorolipid have been identified to possess varying antagonism relationship to a number microbiota, although having been identified as being ecologically friendly. The biosafety of biologically synthesized materials has been identified as a major challenge to commercialization and scale-up. Sophorolipid was produced by Candida haemulonis and Saccharomyces cerevisiae in Palm oil mill effluent impacted soil in Emohua, Rivers State. Submerged fermentation was employed in the production of the sophorolipid while the Well-in-agar approach was employed in the antimicrobial susceptibility was conducted using 20%, 40%, 60%, 80% and 100% on both beneficial and pathogenic bacteria and fungi namely Staphylococcus sp, Nitrobacter sp, Klebsiella sp, Bacillus sp while the fungal flora were Aspergillus sp, Penicillium sp, Rhizopus sp, Candida sp, Mucor sp and Saccharomyces sp. Acute toxicity was conducted using Nitrobacter sp, Nitrosomonas sp and Thiobacillus sp. Probit based determination of acute toxicity after a 48hr and 96hr exposure to the test organisms. Antagonistic nature of the sophorolipids showed there was little or no antagonistic activity on the bacterial isolates than the fungal isolates. The sophorolipid formulation synthesized from both isolates were observed to have a zone of inhibition between 10 mm to 24 mm for Nitrosomonas sp. while to Aspergillus sp it had a range between 4.0 mm to 13.0 mm. Acute toxicity of sophorolipid produced by Candida haemulonis against Nitrosomonas sp 0.054 mg/L while to Thiobacillus sp it had an acute toxicity index of 0.107 mg/L.  This study identified that the sophorolipid produced by the yeast isolate had the potential of being employed in a number of sectors. This study has pioneered the untapped benefits in the POME-induced flora and how they can be veritable tools in the biotechnology industry.

Open Access Original Research Article

Callus Induction, Regeneration and Establishment of Rice Plant from Mature Embryo

Nazmul Alam Khan, Md. Imtiaz Uddin, Md. Shohel Rana, Nusrat Jahan, Mirana Akhter Sumi, M. Harun-or Rashid

Journal of Advances in Biology & Biotechnology, Page 10-18
DOI: 10.9734/jabb/2021/v24i930238

Plant growth regulators were used to test callus induction and in vitro regeneration in six rice genotypes (RM-AC-2, BRRI dhan89, BRRI dhan88, Nipponbare, Koshihikari and Zenshan97). Four different concentrations (1, 2, 3 and 4 mg/L) of 2,4-D for callus induction and three different concentrations (1,2 and 3 mg/L) of NAA with three doses (5,10 and 15 µ/L) of kinetin for callus regeneration were used to test the effect of plant growth regulators. This study found a high callus induction on MS medium enriched with 2 mg/L 2, 4-D. In cases of RM-AC-2, BRRI dhan89, BRRI dhan88, Nipponbare, Koshihikari and Zenshan97, callus induction frequencies were 92.7%, 87.8%, 84.6%, 82.9%, 86.2% and 62.9%, respectively. In the regeneration, it was found that an MS medium enriched with 2 g/L Kinetin and 10 µm/L NAA has the ability to induce increased regeneration of different rice varieties (RM-AC-2 (72.4%), BRRI dhan89 (66.9%), BRRI dhan88 (62.5%), Nipponbare (63.3%), Koshihikari (48%) and Zenshan97 (39.6%). From the regenerated plants, one plant of the RM-AC-2 genotype availed to complete its life cycle and generated 32 effective tillers and yielded 89g. This rice plant is very promising for high yielding rice variety development program in Bangladesh. The improved callus development and regeneration ability of this genotype might be helpful for future rice variety development and genetic transformation program.