Int.J.Curr.Microbiol.App.Sci (2016) 5(8): 791-801

International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 5 Number 8 (2016) pp. 791-801 Journal homepage: http://www.ijcmas.com

Original Research Article http://dx.doi.org/10.20546/ijcmas.2016.508.088

Isolation of Nodule Bacteria from indica and Screening of its Efficiency on PHB Production

J. Manju* and P. Prabakaran

Department of Microbiology, Maruthupandiyar College, Vallam, Thanjavur, India *Corresponding author

ABSTRACT

K e yw or ds The present research investigation was aimed to isolate nodule associated

endophytic bacterium and to screen the PHB production efficiency among , Rhizosphe re, different carbon source. The Aeschynomene indica root qualitative

PHA, Budding phytochemical anlaysis reveals presence of all tested phytochemicals except cardiac glycoside.two bacterial genera namely Rhizobium sp nand Blastbacter bacteria, Glycerol . sp were isolated and identified based on biochemical characters. Bot the isolated strains were solublize phosphate, produced Indole acetic acid and failed

Article Info to produce siderophore. Both the isolated bacterial strains were PHB positive in nature. Among the tested bacterial strains maximum of 80% PHB was Accepted: recovered from Blastobacter sp under five percentage Jaggery as carbon source. 24 July 2016 Available Online: The phylogenetic tree reveals that the isolates was found to be Blastobacter 10 August 2016 capsulatus.

Introduction

Soil is considered as host of microbial subclass Proteobacteria,and divide them into activity, though the space occupied by living seven genera: Rhizobium, Agrobacterium, microorganisms is estimated to be less than SinoRhizobium, MesoRhizobium, 5% of the total space and plays an important AlloRhizobium, AzoRhizobium and role in soil processes that determine . Members of the genera productivity (Tilak et al., 2005). The success Rhizobium and SinoRhizobium are of legumes is largely debted to their significant because of their ability to symbiotic relationship with specific nitrogen nodulate the roots of leguminous and fixing bacteria known as rhizobia, a name carry out nitrogen fxation (Keyser et al., that portray root and stem nodulating 1982; Long, 1989). Most rhizobia are host bacteria. Microorganisms collectively specific and several different bacterial belongs to rhizobia are important plant- species are also isolated from a single associated bacteria which have been studied species and it is only from limited extensively over the past few decades. hosts which have been examined as far as Phylogenetic data place the rhizobia and microsymbionts are concerned (Arora et al., Agrobacteria in the alpha-subdivision of the 2001). These rhizobia are characterized into

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Int.J.Curr.Microbiol.App.Sci (2016) 5(8): 791-801 two groups on the basis of growth rate. First polyesters (polyoxoesters) of R- group is fast grower rhizobia and second is hydroxyalkanoic acid (HA) monomers that slow grower rhizobia. The slow growing are biosynthesized by wide range of bacteria have mean generation time greater Microorganisms. Poly (3-hydroxybutyrate), than 6 h and fast growing bacteria have less is the most abundant PHA in nature. than 6 h in selective broth medium (Elkan, However, the application of P(3HB) is 1992). Unlike the genera Rhizobium, limited by its high crystallinity and brittle SinoRhizobium, MesoRhizobium, nature (Sudesh et al., 2000). A variety of BradyRhizobium, AlloRhizobium and PHAs containing 3-hydroxybutyrate (3HB) AzoRhizobium, members of the genus and a second monomer, such as 3- Agrobacterium are unable to nodulating the hydroxypropionate (3HP), 4- roots of leguminous plants, but instead are hydroxybutyrate (4HB), 5-hydroxyvalerate considered to be causing gall disease and (5HV), and 3-hydroxyhexanoate (3HHx), root hair disease (Bradbury, 1986). have been produced to improve material Generally, the endophytic bacteria live properties (Chuah et al., 2013; Fukui et al., inside the plant tissues and do not cause 2009). visible damage or morphological change on their hosts. They can benefit the host plants Materials and Method by the production of IAA (indoleacetic acid, phytohormones), siderophores, and Sample Collection and phytochemistry antibiotic compounds, through nitrogen fixation, by phosphate solubilization, and producing leguminous plants with the suppression of phytopathogens Aeschynomene indica was collected at through competition. Additionally, they may Thanjure district and processed. Collected help the symbiotic rhizobia form nodules Plant sample herbarium was submitted at with non-specific hosts, further aiding plant Botany department, Saint Joshep College, growth (Liu et al., 2010). The occurrence of Tiruchirapalli for identification. Bacillus species as endophytes has been reported from different plants such as pigeon Preparation of extract pea,wheat, kudzu, and soybean nodules. In addition to plant growth stimulations the The collected plant roots were washed; the root nodule endophytes are also capable to bark was peeled off and then dried under produce Poly Hydroxy butyrate polymer shade. The coarse powder of the roots (PHB) due to lack of citric acid cycle inside (76.712g) was soaked in one Liter of 50% the host. PHAs being biodegradable and ethyl alcohol and extracted in the cold for 3 biocompatible have a promising future in days with occasional shaking. The solvent medical related fields. However, their from the total extract was filtered & industrial production is well established, the concentrated on water bath for 8 hrs. The cost of production is not competing to meet remaining was used for the analysis of economic gain of industries. PHAs are Phytochemical test. among the most fascinating and largest groups of biopolyesters, with over 150 Isolation and Identification of nodulating different types of monomer composition that bacteria (Zhang et al., 1996) provide different properties and functionalities (Hazer and Steinbüchel, Endophytes and epiphytes were isolated 2007). They are thermoplastic or elastomeric from root nodules of collected plant.

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Nodules were taken from freshly uprooted Siderophore production test plants. Roots of the plant were thoroughly washed under tap water to remove the mud The chromeazurol (CAS) agar assay was and soil particles. described by Schwyn & Neilands (1987). about 60.5 mg of CAS was dissolved in 50 Healthy and pink nodules were selected for mL of deionised water, and mixed with 10 the isolation of nodule-associated bacteria mL of a Fe3+solution (1 mmol L-1 -1 (NAB). Nodules were safely cut from the FeCl3.6H2O,10 mmol L HCl). While root and were washed under running tap stirring, this solution was slowly mixed with water and then for 30 sec in 70% ethanol 72.9 mg of hexadecyltrimethylammonium solution. They were then treated with 0.1% bromide (HDTMA) previously dissolved in HgCl2 for 2 min and successively washed 40 mL water. The resulting dark-blue three times with sterile distilled water under solution was autoclaved, cooled to 50/60°C aseptic condition for 1 min each. The and mixed with 900 mL sterile MM9 (Silva nodules were put in 1.5 mL microfuge tubes Stenico et al., 2005) containing 15 g L-1 agar containing 0.5 mL N-saline. Then the (also kept at 50/60°C). This medium was nodules were crushed with the help of sterile allowed to gel on Petri dishes, was forceps and the 100 μL contents were spread subsequently inoculated with bacterial on YEMA plate. All the plates were strains and incubated in the dark (28°C for 5 incubated at 28 ± 2°C for 5 days. Colonies days). Positive results were indicated by the were picked after 5 days incubation. The formation of a clear halo around. The cultures were maintained on YEMA slants colonies, showing a visual change in color with regular subculturing from dark-blue to yellow colouration indicates positive. Morphological Characteristics Indole Acetic Acid (IAA) Production All the strains were maintained on Yeast Extract Mannitol Agar (YEMA) as well as Bacterial endophytes were tested for their Yeast extract glucose agar (YEGA) and the ability to produce IAA under liquid culture. rhizospheric strains were maintained on The bacterial cultures were inoculated in Luria Bertani (LB) Broth. All the isolates on tryptone soya broth supplemented with 100 agar plates were checked for their colony μg ml-1 DL-tryptophan and were incubated morphology. Similarly using Gram staining at 30º C for 72 h. Indole acetic acid was technique as described by (Arora, 2003) determined in the culture supernatant by pink colored Gram negative rods were adding Salkowski reagent. Two ml of observed Salkowski reagent was added to 2 ml of culture supernatant, mixed and allowed to Biochemical Tests: All the collected stand for 30 min for the development of pink samples were processed through different colour. biochemical tests viz, Catalase Test, Indole Production Test Methyl Red Test, Vogas Phosphate Solubilization (Ponmurugan and Proskauer Test, Citrate Utilization Test, Gopi, 2006): Phosphate solubilization ability Starch hydrolysis Test, Gelatin liquefaction of the endophytes was determined by Test and Motility Test and ONPG Test (O- spotting of cultures on Pikovskaya’s agar Nitrophenyl-D- Galacto-Pyranoside) as plates. Plates were incubated at 30o C for described by (Cappuccino, 2007). one week and the appearance of clear halo

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Int.J.Curr.Microbiol.App.Sci (2016) 5(8): 791-801 zone around the colonies indicated Effect of Carbon and Nitrogen Types on solubilization of inorganic phosphate by PHB Production bacteria. The halo size produced by the respective bacteria was calculated according For the growth and production of PHB the to the formula: simplified minimal medium (NaCl – 0.01g, NH3HPO4 -6 g; KH2PO4- 3g, MgSO4 - Solubilization Index= zone diameter (cm) - 0.02g CaCl- 0.001g, Fecl3 -10Mm, CaCO3 colony diameter (cm)/ colony diameter (cm) 0.005 g/L and pH at 6.8) and modified Luria-Bertani (LB: casein 10 g; NaCl 10 g, Screening for PHB producing bacteria yeat extract 1g/ L) broth was used. All the medium was supplemented with 5 Preliminary screening by indirect staining percentage of glucose, lactose, mannitol, glycerol and jaggery as sole carbon source. All the bacterial isolates were qualitatively tested for PHB production following the The fermentation medium was prepared and viable colony method of screening using sterilized at 121°C and 1% inoculum was Sudan Black Dye (Jeran et al., 1998). For added to each flask to carry out this screening of PHB producers, YEMA fermentation. The flasks were incubated at media supplied with 1% of glucose was 37°C under 200 rpm for 78hrs. Samples autoclaved at 1210 C for 20 min at 15 lbs were collected at 48 hrs and the cell biomass pressure. This media was poured into sterile was measured at 600nm using Petri plates and allowed for solidification. spectrophotometer. The plates were divided into 5 equal parts and bacterial isolates were spotted. These Quantitative analysis of PHB plates were incubated for 24 hours. Now ethanolic solution of 0.02% Sudan Black B After 72 hrs Fermentation on broth at 37° C, was spread over the Petri plates containing culture was collected and centrifuged at colonies and was kept undisturbed for 30 10,000 rpm for 15min and lyophilized. The min. They were washed with 96% ethanol to lyophilized pellet was digested with 4% remove excess stain from colonies. sodium hypochlorite solution for 20min.

Secondary screening by direct staining Then pellet was collected by centrifugation at 10,000 rpm for 15min, washed with Sudan black staining water, acetone, ethanol respectively for washing and extraction. Finally polymer was Thin smear was prepared and thoroughly air dissolved in chloroform and kept for dry. Stain with Sudan black B solution and complete evaporation. Dry weight of let it stand for 10-15 minutes. Add more extracted PHB was estimated as g/L. stain if the slide starts to dry out. Wash the Residual biomass was estimated as the slide with xylene and counter stain with difference between dry cell weight and dry safranin for 10 seconds. weight of PHB.

Wash with distilled water and blot dry with The percentage of intracellular PHB tissue paper. Examine the slide under oil accumulation is estimated as the percentage immersion microscope for PHB granules. composition of PHB present in the dry cell Organism shows positive in blueviolet and weight (Arnold et al., 1999). shows negative in yellow-brown 794

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Residual biomass (g/ml) = DCW (g/ml) – all biochemical except utilization of citrate. Dry weight of extracted PHB (g/ml) This isolate differ from Rhizobium sp on PHB accumulation (%) = Dry weight of indole, gelatin and starch utilization which extracted PHB (g/ml) × 100 / DCW (g/ml) was positive by Blatobacter and negative in Rhizobium sp. Results and Discussion Eventhough the Rhizobium is the most The collected plant sample was identified as common nodulation bacteria rare isolates Aeschynomene indica and the accession like Blatobacter spp. which are freshwater number is SJCBT2102. Phytochemical study bacteria that form rosette structures by reveals the presence of carbohydrate, cellular attachment to a common base was saponins, phenol and tannins, steroid also isolated and reported by Peter van glycoside, flavanoid and alkaloids (table 1). Berkum, and Eardly during 2002. Aside from their ability to form nitrogen- fixing nodules on both the roots and stems Both the isolated strins showed positive of tropical aquatic legumes of the genus result on PHB sudan black staining (plate 1 Aeschynomene, the photosynthetic b). Among the tested medium LB broth with bradyrhizobia exhibit several other nitrogen source casein showed maximum remarkable features. First, their growth of both strains. LB with 5% glucose photosynthetic character, which is a rare and glycerol showed 68% of PHB polymer. property among rhizobia, contributes to Whereas minimal medium with ammonium symbiotic efficiency by providing energy to as nitrogen source showed moderate growth the bacteria that can be used for nitrogen rate but the occumulation of PHB is high. fixation. Second, they are able to fix Among the five different carbon sources nitrogen in the free-living state (Alazard, MM with jaggery showed maximum PHB 1990). accumulation followed by Glycerol. Isolate belongs to Rhizobium showed 70% of PHB Totally 6X 10-6 colonies were isolated and on MM with Jaggery and a minimum of identified as Gram negative based on 68% on LB broth with glucose. mucoidal and pink colonies, cell wall by Grams stain found as rod and pleomorphic The maximum PHB occumulation 80% was cells (plate 1 a) and Bichemical characters observed in Blatobacter sp which was (Table 2) confirms that the isolates are grown in MM with Jaggery and minimum of belongs to Rhizbium sp and Blatobacter sp. 74% with glycerol. Production of PHB on Most of the colonies were glistering mucoid LB broth was less significant than minimal in nature and few colonies were pale pink medium by these isolates. However LB with raised in nature. Both the isolates were glucose and Glycerol showed moderate PHB siderophore negative but solublize the production (44%) but lees significant on phosphate. Lactose and mannitol (figure 1 and 2). Figure 3 shows the 16S rDNA relatedness It was observed that the phosphate of Blatobacter sp reveals that it closely solublization index of Rhzobium sp was related to Blatobacter capsulatus with 99% 62% and 55% for Blatobacter sp. Test on similarity and the Genbank accession indole acetic acid shows positive result only number is KU713053. on Rhizobium sp. Isolate belongs to Blatobacter (S2/2) showed positive test on

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Table.1 Qualitative analysis of Phytochemical of root of Aeschynomene indica L

S.No Phyto chemical test interference Aeschynomene indica

1. Carbohydrate test L

a) Benedict’s test Brick red- positive positive b) Fehling’s test Brick red- positive positive c) Iodine test Purple- positive positive

2. Saponins test Stable foam- positive positive

3. Phenols and tannins test Black colour- positive positive

4. Glycoside test Reddish brown- positive positive

Salkowski’s test ( steroid ring)a) Keller Kilani test Brown ring- positive negative

(cardiac glycoside) 5. Flavonoid test- Shinoda test Pink colour- positive positive

6. Alkaloids test- Wagners test Precipitation- positive positive 7. Quinones test Red colour- positive positive

8. Terpenoids test Red brown- posiive positive

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Table.2 Biochemical characters of isolated bacterial strain Sample Colony Gram Cat Oxi Indole MR VP citrate ONP Gelati starc PHB Phosphate code morphology staining d G n h solublizaion

S-2 Aeschynomene indica

1 Large, negative rod + + - + + - + - - + 60 White mucoid, glistering 2 Pale pink, negative, + + + + + - + + + + raised, pleomorphic 55 opaque

Fig.1 Effect of carbon source on PHB accumulation by Rhizobium sp

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Fig.2 Effect of carbon source on PHB accumulation by Blatobacter sp

Fig.3 Phyogenetic relatedness of Blatobacter strain KU713053

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Plate 1 a) Gram’s Staining

S2/ Rhizobium spp S2/2 Blatobacter spp b) PHB staining

S2/ Rhizobium spp S2/2 Blatobacter spp

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Despite these advantages, production costs nodules of tropical Aeschynomene of bioplastics remain higher than those of species. FEMS Microbiol. Lett., 68, conventional plastics and will need to be 177–182. lowered for bioplastics to compete in the Arora, N.K., Kang, S.C., and Maheshwari, marketplace (Choi and Lee, 2000). The D.K. 2001. Isolation of siderophore overall cost of polymer production could be producing strains of Rhizobium decreased by the efficient use of inexpensive meliloti and their biocontrol potential carbon feedstocks (Nikel et al., 2006). against Macrophomina phaseolina that Several studies have investigated the causes charcoal rot of groundnut. production of bioplastics from industrial Curr. Sci., 81: 673-677. waste streams. In this study five different Bradbury, J.F. 1986. Agrobacterium. In A carbon sources were tested and it was Guide to Plant Pathogenic Bacteria, observed that the cheapest carbon source pp. 6±15. Farnham Royal: CAB jaggery was given a luxuriant PHB International Mycological Institute. production. Frequency of production of Cappuccino, G., James, and N. Sherman. 2007. PHB% by Rhizobium sp (Fig 1) was Microbiology A Laboratory Manual. 68>40>44>68>48 respectively for glucose, New Delhi: Dorling Kindersley. 53-165 lactose, mannitol, glycerol and jaggery on p. LB and 58>42>38>46>52 for Blatobacter Chuah, J.A., Yamada, M., Taguchi, S., sp (Fig 2). Similarly growth on Minimal Sudesh, K., Doi, Y., and Numata, K. medium, Rhizobium sp showed 2013. Biosynthesis and 60>34>38>54>60% and characterization of 66>44>38>74>80% by Blatobacter sp., The polyhydroxyalkanoate containing 5- fermentation of these substrates yields hydroxyvalerate units: effects of 5HV favorable amounts of cell mass and units on biodegradability, cytotoxicity, bioplastic with few statistical approaches mechanical and thermal properties. like agitation have been taken to enhance the Poly Degrad Stab. 98, 331–338. doi: production of the desired polymer products. 10.1016/j.polymdegradstab.2012.09.0 Cell dry weight and PHB accumulation was 08. increased significantly under increasing Elkan, G.H. 1992. of the rhizobia. concentration of Jaggery 1>2>4>5 % against Can. J. Microbiol., 38, 446-450. 0.6% nitrogen source. Further Fukui, T., Yokomizo, S., Kobayashi, G., Doi, characterization of PHB like IR and NMR Y. 1999. Co-expression of are required to find out the chemical nature polyhydroxyalkanoate synthase and of isolated PHB. (R)-enoyl-CoA hydratase genes of Aeromonas caviae establishes In conclusion, PHB producing Rhizobium sp copolyester biosynthesis pathway in and Blatobacter sp were isolated from root Escherichia coli. FEMS Microbiol. nodule of Aeschynomene indica. This study Lett., 170, 69–75. doi: 10.1111/j.1574- also concludes jiggery was found to be best 6968.1999.tb13356.x. and cheapest carbon substitute for the Hazer, B., and Steinbüchel, A. 2007. production of PHB. Increased diversification of polyhydroxyalkanoates by References modification reactions for industrial and medical applications. Appl Alazard, D. 1990. Nitrogen fixation in pure Microbiol Biotechnol., 7, 74: 1–12. culture by rhizobia isolated from stem 800

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Keyser, H.H., Bohlool, B.B., Hu, B. and phosphate activity by phosphate Weber, D. 1982. Fast growing solubilizing bacteria. Afr. J. rhizobia isolated from root nodules of Biotechnol., 5: 348-350. soybean. Sci., 215: 1631-1632. Schwyn, B., and Neilands, J.B. 1987. Liu, J., Wang, E.T., Ren, D.W., Chen, W.X. Universal chemical assay for the 2010. Mixture of endophytic detection and determination of Agrobacterium and SinoRhizobium siderophores. Anal. Biochem., 160(1): meliloti strains could induce 47-56. nonspecific nodulation on some Tilak, K.V.B.R., Ranganayaki, N., Pal, K.K., woody legumes. Arch. Microbiol., De, R., Saxena, A.K. (2005) Diversity 192: 229-234. of plant growth and soil health Long, S. 1989. Rhizobium±legume supporting bacteria. Curr. Sci., 89: nodulation: life together in the 136-150. underground. Cell, 56: 203-214. Zhang, F., Dashti, N., Hynes, R.K., and Peter van Berkum, and Bertrand D. Eardly. Smith, D.L. 1996. “Plant growth 2002. The Aquatic Budding Bacterium promoting rhizobacteria and soybean Blatobacter denitrificans Is a [Glycine max (L.) Merr.] nodulation Nitrogen-Fixing Symbiont of and nitrogen fixation at suboptimal Aeschynomene indica. Appl. Environ. root zone temperatures,” Annals of Microbiol., 68(3): 1132-113 Bot., vol. 77(5): 453–459. Ponmurugan, P., and Gopi, C. 2006. In vitro production of growth regulators and

How to cite this article:

Manju, J., and Prabakaran, P. 2016. Isolation of Nodule Bacteria from Aeschynomene indica and Screening of its Efficiency on PHB Production. Int.J.Curr.Microbiol.App.Sci. 5(8): 791- 801. doi: http://dx.doi.org/10.20546/ijcmas.2016.508.088

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