Category Archives: b_original_articles

Oghenerobor B. Akpor^1*, Elisha O. Ezekudo¹, Oguntope A. Sobajo¹, Paul A. Edoh², Samson O. Mabayoje¹

¹Department of Biological Sciences, Afe Babalola University, Ado-Ekiti, Ekiti State, Nigeria

²Department of Civil Engineering, Afe Babalola University, Ado-Ekiti, Ekiti State, Nigeria

Abstract

Biosurfactants of microbial origin are metabolites; hence their production is dependent on the growth of the producing microbe. The objective of this study was to assess the optimum conditions for biosurfactant by four bacterial species. Biosurfactant detection was carried out using emulsification index, drop collapse and oil displacement assays. Functional composition of the crude biosurfactant was determined using gas chromatography-mass spectroscopy (GC-MS). In the presence of Pseudomonas fuscoginae significantly higher EI₂₄ of 53.98% and 52.60% was observed in media that contained glucose or sodium acetate as carbon source, respectively. When P. fuscoginae or P. aeruginosa was used for inoculation, highest EI₂₄ of 61.18% and 48.40% was observed in media that contained potassium nitrate as nitrogen source. In the medium that was inoculated with either B. subtilis or B. proteolyticus, highest EI₂₄ of 53.65% and 49.63% was observed in the presence of tryptone and peptone, respectively. At the respective pH used for investigation, significantly highest EI₂₄ was observed at pH 6, when inoculated with the respective isolates. In the case of incubation temperature, positive results were obtained throughout the incubation period at 25 and 30 ^oC. This was also irrespective of the isolate used for inoculation. All the extracted biosurfactants showed antimicrobial potentials against the test pathogens used for investigation. Characterization of the crude biosurfactant revealed the presence of compounds with antimicrobial properties. The study was able to provide useful information on optimum conditions for biosurfactant production by test bacterial species and the potential for possible application of the biosurfactants as antimicrobial agents.

Keywords: Biosurfactant, Surface tension, Emulsification, Bacterial species

Bilal Ibrahim Wreikat^*

Department of Plant Production and Protection, Faculty of Agricultural Technology, Al-Balqa Applied University, Al-Salt, Jordan

Abstract

The virulence gene Catechol 1,2-dioxygenase was detected in different isolates of Pseudomonas savastanoi pv. savastanoi (Smith, 1908), through amplification of 857 bp band by Polymerase Chain Reaction, it was confirmed in all isolates that were isolated from different olive cultivars growing in different areas in Jordan. Also, digestion of the amplified PCR product of this gene for all isolates of the pathogen, using Polymerase Chain Reaction Restriction-Fragments Length Polymorphism (PCR-RFLP), it was found that the catA gene is highly conserved for all isolates, after digestion with KpnI and BamHI Endonucleases. Further identification was performed for all isolates; by biochemical tests and pathogenicity on olive seedlings, and detection the virulence gene iaaL through PCR amplification of 454bp in all isolates. Interestingly, this study revealed that detection and identification of Pseudomonas savastanoi pv. savastanoi by catA gene is reliable and certified and will give further prospects in management between olive knot through crosstalk of olive plant and their knot bacterium.

Keywords: Olive Knot, Pseudomonas savastanoi, Catechol dioxygenase, Virulence factor

Umi Fatmawati^1*, Dewi Puspita Sari¹, Slamet Santosa¹, Sri Martina Wiraswati²

¹Biology Education Study Program, Faculty of Teacher Training and Education, Universitas Sebelas Maret, Surakarta, Central Java, Indonesia

²Biology Study Program, Faculty of Biology, Universitas Jenderal Soedirman, Purwokerto, Central Java, Indonesia

Abstract

Plant Growth-Promoting Rhizobacteria (PGPR) are microbes that inhabit the rhizosphere and rhizoplanes environment and can enhance plant growth. The application of PGPR in agriculture can reduce the use of chemical fertilizers on soil. The purpose of this study was to determine the ability of the actinobacteria consortium to produce Indole-3-Acetic Acid (IAA), solubilize phosphate, and improve soybean growth in the greenhouse. The results of this study showed that the actinobacteria (Streptomyces sp. ASR58, Streptomyces sp. ASR67) and Rhizobium sp. which are used in this study are mutually compatible and tolerant to several types of fungicides and bactericides. Meanwhile, the consortium of Streptomyces sp. ASR58 and Streptomyces sp. ASR67 produces the highest concentration of IAA i.e. 25.11 ppm compared to each isolate and other bacterial consortia. Accordance to the quantitative phosphate solubilization assay, Streptomyces sp. ASR67 resulted in the highest dissolved inorganic phosphate i.e. 179.7 + 13.3 mg / L. Inoculation of Streptomyces sp. ASR58 and Streptomyces sp. ASR67 consortium into soybean seeds can significantly increase 54.6% in stem length, 29% root growth, and 20.4% in plant dry weight. This research indicated that Streptomyces sp. ASR58 and Streptomyces sp. ASR67 consortium resulted in the best growth toward soybean plants compared to other bacterial  consortia.

Keywords: Actinomycetes, IAA, Phosphate solubilization, Rhizosphere

Wardah1, Yasinta Lahum2, Feronika Fuakubun2, Tatang Sopandi2

1Study Program of Agroindustry, Vocational Faculty, Universitas 17 Agustus 1945, Surabaya, East Java, Indonesia

2Study Program of Biology, Faculty of Science and Technology, Universitas PGRI Adi Buana, Surabaya, East Java, Indonesia

Abstract

The valorization of industrial poultry waste by microbes into value-added products has received significant attention for reducing pollutants and producing a healthy environment. The current study aims to explore the use of liquid fertilizer from fermented chicken feathers by Bacillus cereus and Bacillus subtilis. The study was carried out experimentally ki using a completely randomized trial design with 10 different treatments of liquid fertilizer, each of which was repeated 12 times. The current study showed that both bacteria can secrete keratinase enzymes, degrade chicken feathers, and increase the nitrogen content of liquid fertilizer. However, the keratinase activity, degradation, and nitrogen content of chicken feather liquid fertilizer produced by B. subtilis fermentation were significantly higher (P˂0.05) than those of B. cereus. Likewise, the growth, anthocyanin content in the leaves, and yield of red spinach plants nurtured with chicken feather liquid fertilizer from B. subtilis fermentation were significantly (P˂0.05) higher than those given liquid fertilizer from B. cereus. The current study concluded that chicken feathers could be valorized into liquid fertilizer for plants, especially red spinach, by both B. cereus and B. subtilis bacteria. The current study recommends liquid fertilizer from chicken feathers fermented by B. subtilis at 0.05 g/plant to replace chemical fertilizers in plants, especially red spinach.

Keywords: Bacillus cereus, Bacillus subtilis, Chicken feather, Keratinase, Red spinach

Muhammad Ehsan Safdar¹, Amir Ehsan¹, Rizwan Maqbool², Amjed Ali¹, Rafi Qamar^1*, Hasnain Ali³

¹Department of Agronomy, College of Agriculture, University of Sargodha, Pakistan

²Department of Agronomy, Faculty of Agriculture, University of Agriculture, Faisalabad, Pakistan

³Masters of Business Administration Program, Holmes Institute, Gold Coast, Australia

Abstract

In the present era, direct-seeding is a viable alternative of traditional transplanting of rice for farmers due to water and labour shortage. It has the potential to ensure water and labour saving along with higher productivity of water. Study was performed to assess the critical period of weed-crop competition i.e. time period during which weeds cause maximum reduction of yield in dry direct-seeded basmati rice during two consecutive summer seasons of the years 2015 and 2016. This experiment consisted of 6 weed competition periods [0, 2, 3, 4, and 5 weeks after crop emergence (WAE)] and 6 weed-free periods (0, 2, 3, 4, and 5 WAE) by mixed weed flora. The experiment was executed in randomized complete block design having four replications. With the increasing duration of the weed-crop competition, the productive tillers, grains per panicle, and 1000-grain weight were decreased gradually. A whole season competition with mixed weed flora reduced rice grain yield up to 90% and increased N, P, and K uptake by weeds up to 28, 5, and 28 kg ha^-1, respectively. In dry direct-sown rice, the critical time of weed removal as estimated by the three-parameter logistic model was 1.4-6.3 WAE and 2.8-4.8 WAE to save 10 and 20% grain yield, respectively. Hence it is concluded that dry direct-seeded rice crop should be kept weed free during this time period of crop growing season.

Keywords: Direct-seeded rice, weed-crop competition, critical time, yield.

Chengfang Li¹, Shahrear Ahmad^2*, Cougui Cao¹

¹MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Researches of the Yangtze River, College of Plant Sciences and Technology, Huazhong Agricultural University, Wuhan 4300, PR China

²Department of Botany, Jagannath University, Dhaka 1100, Bangladesh

Abstract

We have tested the tillage combination to study methods that help curtail the release of greenhouse gasses from rice paddy fields have had on the climate and contrasted the potential outcomes for rice production (Oryza sativa L.), no-tillage plus no fertilizer (NT0), conventional tillage plus no fertilizer (CT0), conventional tillage plus compound fertilizer (CTC), no-tillage plus compound fertilizer (NTC) by measuring ammonia volatilization and greenhouse gases emissions (GHG) from paddy fields for rice throughout the year of 2018 in the subtropical area of central China. The mean NH₃ volatilization in CT0 was 9.55% greater than that in NT0 by (p>0.05), and for NTC, it was 11.30% (p>0.05) lower than in CTC. In comparison to CT0, the mean CH₄ emission flux in NT0 was 1.12% (p>0.05) lower, but the mean CH₄ emission flux in CTC was 28.34% (p> 0.05) higher than that in NTC. The mean N₂O emission flux in NT0 was 174.72% (p˂0.05) lower than in CT0. The average flux of N₂O emission in CTC was 47.90% (p˃ 0.05) greater than in NTC. We compared the IGWPs based on N₂O, CH₄, and CO₂ emission flux. CT0 had the lowest (non-significant) recorded amount at 12097.43KgCO₂.ha^-1 of GWPs, which was only 397.5KgCO₂.ha^-1 lower than that in NT0. CTC had the highest recorded amount at 20042.72KgCO₂.ha^-1 of GWPs, which was 2292.53KgCO₂.ha^-1 higher than that reported in NTC. NTC system to be the superior, sustainable method for mitigating the harmful effects of GHG emissions contributing to the climate crisis by way of rice production in rice paddy fields.

Keywords: Rice cultivation, Climate crisis, No-tillage, Conventional tillage, GHG, NH₃ volatilisation