Isolation and characterization of nitrogen-fixing bacteria from soil sample in Dhaka, Bangladesh

Biological nitrogen (N2) fixation is very essential for limiting the growth of plants and agricultural crops. The present study was conducted to potentially isolate N2-fixing bacteria from garden soil sample at Stamford University Bangladesh, Siddeswari, Dhaka. Here, we used culture-dependent method to perform this experiment. Firstly, we collected garden soil sample, diluted and inoculated in N2-free Jensen’s media by maintaining the aseptic procedure. We obtained 5 different colonies from soil samples. We cultured the isolates in N2-free Jensen’s media containing bromothymol blue (BMB) and also, in Yeast Extract Mannitol Agar (YEMA) media containing congo red to confirm nitrogen fixation capacity. We collected the colony characteristics of all the isolates. Only 1A isolate showed good growth after 24 h of incubation among all the isolates. We performed ammonification test with Nessler reagent to confirm N2-fixing ability for our selected isolates. The 1A isolate was positive in ammonification test. Culture, microscopy and biochemical tests were performed to identify isolate 1A. This isolate was presumptively identified as Azotobacter sp. In the present study, Azotobacter sp. that was isolated from the soil sample was found to be a potential N2-fixing bacterium. Isolate 1A can be used for N2-fixation to boost production of crops. Stamford Journal of Microbiology, Vol.11 (1) 2021: 11-13

Root- Nodulating Ensifer Adhaerens Ks23 of Pisum Sativum L. In Optimisation of Cadmium Biosorption Using Rsm Based Approach

The Cadmium tolerance by root nodulating bacteria Ensifer adhaerens KS23 inhabiting in Pisum sativum L. var. Arkel revealed linear relationship with inorganic salt cadmium sulphate (CdSO4) upto 200 μg/ml, corresponding to growth and survival in solid as well as liquid Yeast Extract Mannitol (YEM) medium with LC50 value of 107.2 μg/ml and LC95 of 184.5 μg/ml. The results of phylogenetic and morpho-physiological analysis exhibited the genus E. adhaerens. KS23 was found to be the most promising among all the 20 isolates. The increase in Glutathione S-transferase (GST) activity by KS23 was 9.7 fold under Cd stress. Wherein, P and F values were <0.05 and 26.54 respectively and predicted r2 value of 0.8192 and adjusted r2 value 0.8908 were reasonable (i.e. <0.2) of the Box Behnken design. The data showed that 81.24% cadmium bio-removal achieved at pH 6.0, 30°C and 168 h of incubation while supplementing the YEM medium with 25 μg/ml cadmium. Further, its effect on plant growth and development exhibited due to production of IAA, secretion of siderophores, phosphate solubilisation and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity by E. adhaerens KS23. In addition to inherent PGP attributes, Cd tolerant E. adhaerens KS23 played dual role of biosorption of cadmium and upsurge in growth promotion of P. sativum which may provide a new root-nodulating bacterium inhabiting in P. sativum cultivated at high altitudes of Himalayan region.

EFFECTS OF SELECTIVE HERBICIDE, ATRAZINE ON THE RHIZOBIUM POPULATION AND NODULATION OF GROUNDNUT (ARACHIS HYPOGEAE)

Atrazine is a selective herbicide used to control weeds in farm operations. The effect of different concentrations of atrazine on Rhizobium population and nodulation in groundnut (Arachis hypogeae) was investigated using Yeast Extract Mannitol Agar (YEMA). The test crop was planted for 90 days after the soil was treated with the various concentration of atrazine. The following parameters; Rhizobium count, nodule count, plant height and germination percentage were observed. The total Rhizobium count obtained at 0% atrazine treatment has 3.0 x 108, 0.1% has 2.9 x 108, 0.5% has 2.5 x 108, 1% has 2.0 x 108, and 3% has 1.4 x 108 all in cfu/ml while the number of root nodules formed was also counted after uproot which was; 0% atrazine treated has 50 nodules, 0.1% has 50 nodules, 0.5% has 30 nodules, 1% has 23 nodules and 3% has 19 nodules. The study revealed that the higher the atrazine concentration the lower the population of Rhizobium, the numbers of root nodules increased with decrease in atrazine concentration and Plant height, root length and germination percentage was also affected adversely by increased in atrazine concentrations.

Plant Pellets: A Compatible Vegan Feedstock for Preparation of Plant-Based Culture Media and Production of Value-Added Biomass of Rhizobia

Although plant-based culture media enhances in vitro cultivation of rhizobacteria, studies assessing their biomass potential for large-scale applications are lacking. Here, we advance plant pellets (PPs) as a novel technology to unlock the potential of such vegan culture media for biomass production of Rhizobium leguminosarum. PP formulations were based on mixtures of Egyptian clover powder and the agro-byproducts glycerol and molasses. These mixtures were either contained or not contained in teabags during culture media preparation. Metrics of biomass included colony forming units, optical density (OD600nm), and cell dry weight (DW). Biomass comparisons between culture media based on PPs and standard yeast extract mannitol (YEM) revealed that the following PPs composition, contained in teabags, cultivated rhizobia at levels comparable to YEM: 16 g clover powder, 5% molasses, and 0.8% glycerol. This PPs composition enabled shorter generation times of rhizobia (PP: 3.83 h, YEM: 4.28 h). Strikingly, PPs mixtures supplemented with 10% molasses and not contained in teabags promoted rhizobia without apparent lag phases and produced 25% greater DW than YEM. PPs potentiate the use of dehydrated vegan feedstocks for both plant microbiota cultivation and biomass production and appear as cost- and labor-effective tools, easy to handle and store for plant-based culture media preparation.

KARAKTERISTIK DASAR POPULASI BAKTERI PENAMBAT NITROGEN NON-SIMBIOTIK PADA LAHAN GAMBUT BEKAS KEBAKARAN

Nitrogen is an macroessential nutrient for plant growth. Insufficient nitrogen or nitrogen elements, the plant will be upnormal. The availability of nitrogen can be obtained through one of the microbes in the soil, namely nitrogen fixing bacteria (NFB) that is capable of fixing free nitrogen, including symbiotic and non-symbiotic. This study aimd to describe the density of population and the basic characteristics of NFB in burnt peatland Kuala Dua village. The method was in soil sampling with systematic sampling. Bacteria isolation using yeast extract mannitol agar (YEMA) media by using the pour plate method. The density of bacterial population was calculated by count pour method. The result showed tha the higest population density in peat from at distance of 80 m from the edge of the trench with a depth of 0-20 cm as much (52.107cfu/g soil), while a low population density was found at a distance of 20 m from the edge of a trench with a depth of 20-50 cm by much (15,5.107cfu/g soil). The bacterial population in burnt peatland fall was categorited the high. there potential can developed to support the restoration of peatland ecosystems originating from burnt peatlands.Keywords: charakteristics, burnt peatlands, nitrogen fixing bacteria, restoration.

Potensi Mikroorganisme sebagai Biofertilizer dari Limbah Cair Pabrik Kelapa Sawit

This research was carried out in the oil palm plantation of PT. MuliaSawitAgro Lestari (PT. MSAL) Gunung Mas Regency Central Kalimantan Province for three months starting in January 2019 until March 2019. The purpose of this study was to identify the potential of microorganisms as biofertilizers from palm oil mill effluent (PKS). This research is an exploratory study conducted in the Laboratory of the Faculty of Health Sciences of the Muhammadiyah University of Palangka Raya. This study used 3 (three) media used to identify the potential of microorganisms for biofertilizer from palm oil liquid waste by calculating the number of bacterial colonies namely Carboxy Methyl Cellulose (CMC), pykovskaya media and Yeast Extract Mannitol Agar (Yema) media. The results of the analysis also showed that PKS liquid waste contained potential microorganisms found were phosphate solvent bacteria, cellulite fungi and nitrogen-fixing bacteria with an average bacterial colony of 1,700,000 cells/mL. Potential microorganisms from the proportion obtained showed the ability of bacteria found in PKS liquid waste to degrade the oil. The first and second samples of bacterial forms identified were in the form of bacilli and were gram-positive bacteria, while the samples of the three bacteria were in the form of coccus and the bacteria were gram-negative bacteria.

POTENSI MIKROORGANISME SEBAGAI BIOFERTILIZER

This research was carried out in the oil palm plantation of PT. MuliaSawitAgro Lestari (PT. MSAL) Gunung Mas Regency Central Kalimantan Province for 3 months starting in January 2019 until March 2019. The purpose of this study was to identify the potential of microorganisms as biofertilizers from palm oil mill effluent (PKS). This research is an exploratory study conducted in the Laboratory of the Faculty of Health Sciences of the Muhammadiyah University of Palangka Raya. This study used 3 (three) media used to identify the potential of microorganisms for biofertilizer from palm oil liquid waste by calculating the number of bacterial colonies namely Carboxy Methyl Cellulose (CMC), pykovskaya media and Yeast Extract Mannitol Agar (Yema) media. The results of the analysis also showed that PKS liquid waste contained potential microorganisms found were phosphate solvent bacteria, cellulite fungi and nitrogen-fixing bacteria with an average bacterial colony of 1,700,000 cells/mL. Potential microorganisms from the proportion obtained showed the ability of bacteria found in PKS liquid waste to degrade the oil. The first and second samples of bacterial forms identified were in the form of bacilli and were gram-positive bacteria, while the samples of the three bacteria were in the form of coccus and the bacteria were gram-negative bacteria.

Study of an arsenic metabolizing bacteria from arsenic contaminated soil of Chandpur district, Bangladesh

Arsenic is a toxic metal found as inorganic oxyanion arsenate As(V) and arsenite As (III) species. The disposal of toxic heavy metals such as arsenic poses high risk to environment. The present study was undertaken to isolate arsenic-metabolizing bacteria from arsenic contaminated soil of Chandpur district, which is one of the most arsenic contaminated area in Bangladesh and later these bacteria were screened for their ability to metabolize arsenate. Out of ninety eight isolates, ten were found to be capable of metabolizing arsenic in Yeast Extract Mannitol (YEM) medium containing 2 mM arsenate at 37ºC. One of the bacterial isolates designated as I-25 was found to produce an extracellular enzyme which can reduce As(V) into As(III) and able to grow in presence of up to 500 mM arsenate. Subsequent molecular identification of this enzyme producing bacterial isolate using 16s rRNA sequence analysis was correlated with previously identified isolate as Bacillus aryabhatti. Further characterization of the enzyme showed that optimum pH of the extracellular enzyme by the bacterial species was 7 and optimum temperature for the enzyme activity was 60ºC. The bacterial isolates can be exploited for the study of possible bioremediation of arsenic contamination. Jahangirnagar University J. Biol. Sci. 8(1): 57-65, 2019 (June)

NodC-based evaluation of the occurrence of bacteria in nodules of Pisum sativum isolated on YEM agar

SummaryThe bacterial nodulation (nod) genes are essential in the formation process of root nodules. This study was aimed to verify the occurrence of nodule-associated bacteria in two pea varieties (“Tarchalska” and “Klif ”) inoculated withRhizobiuminoculants – Nitragine™ and a noncommercial one produced by the Polish Institute of Soil Science and Plant Cultivation (IUNG). The number of colonies isolated on yeast extract mannitol (YEM) agar from the nodules of “Klif ” inoculated with IUNG inoculants was significantly higher than the number of colonies isolated from other variants. Species identification was based on sequencing of 16S rDNA, which revealed that despite careful sterilization of nodules, sequences of other bacterial species were detected. Among them, one sequence belonged toRhizobium leguminosarum(isolated from IUNG inoculant). To assess the presence of nodulation-capableRhizobium, amplification of thenodCgene was performed, which revealed that of 29 samples, 19 were positive. The remaining isolates, including reference strain and bacteria isolated from Nitragine™, lacked this gene. The results show that pea nodules harbor a very diverse community of bacteria. The lack ofnodCgene in some strains isolated from plants inoculated with Nitragine™ and with IUNG inoculant proves that even ifR. leguminosarumare abundant, they may not be efficient in nodulation.

Evaluation of native Rhizobium leguminosarum bv. viceae of pea plants (Pisum sativum L.) for nodulation efficiency and yield promotion in lentil crop (Lens culnaris Medik.) under acid soil

Most leguminous crops including lentil require neutral to slightly acidic range of soil pH for favourable nodulation and nitrogen fixation. The quest for acid soil compatible Rhizobium leguminosarum bv. viceae strain is important for promotion of lentil crop under rice-lentil rotation in acid soil regions. In this investigation, native R. leguminosarum strains were isolated from the nodules of pea plants grown in pots using acid soil and isolated native Rhizobium strains were confirmed on CRYEMA (congo red Yeast Extract Mannitol Agar) media. Four native R. leguminosarum strains (NR1, NR2, NR3 and NR4) obtained from four acid soil types were further screened for nodulation efficiency and yield attributes of lentil crop against a reference exotic strain R. leguminosarum CK1 (ER). The results indicated that the performance of native Rhizobium strain (NR2) was the best among native isolates and performed on par with the reference strain (CK1) in acid soils of Meghalaya.