Indian Journal of Animal Research

  • Chief EditorK.M.L. Pathak

  • Print ISSN 0367-6722

  • Online ISSN 0976-0555

  • NAAS Rating 6.50

  • SJR 0.263

  • Impact Factor 0.5 (2023)

Frequency :
Monthly (January, February, March, April, May, June, July, August, September, October, November and December)
Indexing Services :
Science Citation Index Expanded, BIOSIS Preview, ISI Citation Index, Biological Abstracts, Scopus, AGRICOLA, Google Scholar, CrossRef, CAB Abstracting Journals, Chemical Abstracts, Indian Science Abstracts, EBSCO Indexing Services, Index Copernicus

Isolation of Phosphorus Solubilizing Bacteria from Mangrove Rhizospheric Sediment and its Potential Application in Aquaculture

S. Aruna1,*, D. Manikandavelu1, A. Uma1, Cheryl Antony1, N. Jayakumar1
1Dr. MGR. Fisheries College and Research Institute, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Nagapattinam, Ponneri-601 204, Tamil Nadu, India.

Background: Phosphorus acts as a limiting nutrient in aquatic environments due to its non-availability as it forms insoluble precipitate with Ca, Mg, Fe and Al. Phosphorus solubilising bacteria (PSB) solubilizes the inorganic precipitate into soluble phosphorus. 

Methods: The PSB isolates were screened and isolated from rhizospheric sediment of mangrove, Avicennia marina of Ennore creek, Tamil Nadu. Their phosphorus transformation potential and the possibilities of their application in aquaculture to solubilize inorganic phosphorus were studied.

Result: In the present study, thirteen nos. of PSB isolates were screened from the rhizospheric sediment samples of Avicennia marina collected from Ennore region and identified as Rhodococcus, Arthrobacter, Bacillus, Enterococcus, Staphylococcus and Pseudomonas. The P-solubilizing activity and Acid phosphatase (ACPase) activity of PSB isolates were found to be in the range of 7.62±0.51- 16.33±0.84 mg/l and 4.40±0.28 - 22.77±0.32 mmol ml-1 h-1 respectively. The maximum ACPase activity was exhibited by Arthrobacter sp (22.77±0.32 mmol ml-1 h-1) followed by Rhodococcus sp. (18.08±0.78 mmol ml-1 h-1). The P-mobilizing potential of the isolates obtained in this study were compared with the commercial product following a microcosm study for a period of 21 days. Rhodococcus sp showed higher ACPase activity in sediment (12.00 mmol g-1 h-1) than that of the commercial product (11.23 mmol g-1 h-1).

Phosphorus is one of the essential major nutrients that limits the productivity in the aquaculture ecosystem, even though it is found abundantly in earth’s crust. Because of its high reactive nature, it forms insoluble precipitates or forms complexes with soil and organic matter. Phosphorus solubilising bacteria (PSB) dissociate phosphorus (P) from soil complexes through several mechanisms, such as the production of organic acids that dissolve or chelate inorganic phosphate or the production of phosphatase enzymes that dissociate phosphorus from organic sources. Several studies have reported that bacterial species such as Bacillus, Azobacter, Pseudomonas have the potential to solubilise inorganic P (Sundara et al., 2002; Ghaderi et al., 2008; Amutha et al., 2014). Several studies were carried out to screen PSB from a variety of land ecosystems in search of P mineralising and solubilising microbes for their application as biofertilizers in agriculture (Alori et al., 2017; Garcia - Fraile et al., 2017; Kalayu 2019; Aruna and Jain, 2021). Recent researches are focusing on the screening of salt tolerant microbes in warrant of their application in salt affected land to improve soil fertility (Iwaoka et al., 2018; Zhang et al., 2018; Egamberdieva et al., 2019; Aruna et al., 2023). Very few studies have been carried out to screen PSB in aquatic ecosystems, particularly from mangrove areas. Thus, the present study was carried out to isolate potential PSB isolates from the rhizospheric sediments of Avicennia marina, grey mangroves. As the mangrove region is prone to salinity fluctuation, the bacterial isolates obtained from this region are able to perform nutrient mobilization in low saline conditions to marine conditions. Hence, PSB can serve as a promising tool in integrated nutrient management in aquaculture. Despite high background phosphorus levels due to its non-availability, extraneous phosphorus fertilizers are still used to increase aquaculture primary productivity. The application of salinity-tolerant PSB as biofertilizer will be an effective, eco-friendly and economical means of improving the P availability or soil fertility.
Sampling sites
 
The present study was carried out in the mangroves of Ennore creek, Chennai. The sampling stations are given in Table 1 and Fig 1.
 

Table 1: Sampling stations.


 

Fig 1: Map showing the study area of Ennore creek.


 
Isolation of phosphorus solubilising bacteria 
 
The rhizospheric sediments of Avicennia marina from Ennore region were collected aseptically by carefully removing the soil adhering to 2-3 mm thickness around the individual roots. Serially diluted soil samples were plated on NBIRP medium for selective screening of PSB. The bacterial colony that forms hallow zone around the colony were picked up and pure colonies were obtained by sub-cultured by streak plating method. The study was carried out Dr MGR Fisheries College and Research Institute, TNJFU, Ponneri for the period of 2018-2022.
 
Genomic DNA isolation, 16S rDNA sequencing, RAPD amplification of 16S rDNA
 
The genomic DNA was extracted from the bacterial isolates (using QIAamp genomic DNA kits (Qiagen, Germany) as per manufacturer’s protocol. PCR amplification of DNA using the universal 16S rDNA primer of Weisburg et al., (1991). Nucleotide sequencing (forward and reverse) was done by commercial sequencing services (Eurofins, India). The edited gene sequence was compared against the GenBank database of the National Center for Biotechnology Information (NCBI) by using the BLAST (Basic Local Alignment Search Tool) program (http://blast.ncbi.nlm.nih.gov) and submitted to GenBank.
 
Measurement of P-solubilizing capability of bacteria (PSB) isolates in solid medium
 
The isolated pure strains of PSB isolates were incubated at 37oC for 96 h. The P-solubilizing capacity was observed by measuring the width of the hallow zone between the bacterial colony and outer ring of the hallow zone and its size was measured by the P-solubilizing ring is a clarified area around the bacterial colony (Cao et al., 2018).
 
Measurement of phosphate solubilizing activity of PSB isolates in liquid medium
 
Inoculating One ml of PSB isolate grown at broth culture at 108 CFU/ml in 25 ml of sterilized broth and incubated for 72 h at room temperature at 100 rpm. Then the culture was centrifuged at 10000 rpm for 15 min. And the reactive phosphate in the supernatant was determined spectrophotometrically using ascorbic acid method (Cao et al., 2018).
 
Acid phosphatase (ACPase) assay
 
Inoculating 1 ml of PSB culture at 108 CFU/ml in 25 ml of sterilized broth in a 100 ml conical flask and incubated at room temperature at 100 rpm for 48 h. The samples were withdrawn by centrifuging at 10000 rpm for 10 min at 4oC and ACPase assay was carried out by using para-nitrophenyl phosphate (p-NPP) as organic P substrate (Tabatabi and Bremner, 1969).
 
Production of organic acids
 
Analysis of organic acids was carried out by inoculating the bacterial culture in 50 ml of broth and incubated at 100 rpm and 37oC for 144 h. One ml of incubated sample was centrifuged at 10,000 rpm (Remi laboratories) for 15 min and filtered through 0.2 m membrane filter to obtain cell-free culture supernatant and organic acid analysis was carried out using HPLC (Shimadzu - LC-2010C with Autosampler, FLD and UVE Photochemical Derivatisation). The results were compared with organic acid analysis standards following the methods of Yadav et al., (2013).
 
Microcosm experiment with PSB isolates
 
The study was carried out in a set up of glass tanks (2x1x1 ft). In each tank, the aquaculture pond sediment was placed to 5 cm thickness and 25 L of seawater. The PSB isolates (B. altitudinis, Rhodococcus sp and Arthrobacter sp) isolated from the study and a commercial PSB (FOZBACT, composed of B. megaterium from Ashwathy Green Enterprises Pvt. Ltd) was cultured in 25 ml of marine broth for 3 days at a concentration of 108 CFU/ml. After centrifugation and washing, the pellets of 5ml of the bacterial cultures were inoculated into the microcosm set up. The available P, total P, organic carbon, pH and soil texture were analysed before the start of the experiment. Both water and soil samples were collected from the microcosm set up on Day 0, 2, 4, 6, 8, 10, 12, 14 and 21 for the analysis of phosphorus concentration in water, available-P content and ACPase activity of sediment samples.
Isolation and identification of PSB
 
Bacterial colonies which produced clear transparent zones were isolated and purified by subculturing. Thirteen PSB isolates were obtained and maintained during the study period. PCR amplification of 16S rDNA and sequencing analysis showed the identity of the PSB and the details are provided in Table 2. PSB isolated in this study were identified as Rhodococcus sp, Arthrobacter sp, B. pumilus, B. subtilis, B. paramycoides, B. aryabhattai, B. anthracis, B. altitudinis, Enterococcus sp, Staphylococcus sp (2 nos) and Pseudomonas sp (2 nos). Vazquez et al., (2000) reported that PSB species such as B. amyloliquefaciens, B. licheniformis, B. atrophaeus, Paenibacillus macerans, Vibrio proteolutics, Xanthobacter agilis, Enterobacter sp., Kluyvera cryocrescens, Pseudomonas stutzeri and Chryseomonas luteola from the rhizospheric sediment of black and white mangroves in Mexico. Ravikumar et al., (2009) screened eight PSB isolates namely, B. megaterium, Micrococcus roseus, B. subtilis, Proteus mirabilis, Streptococcus aureus, Micrococcus luteus, Athrobacter illicius and Enterobacter aerogenes from mangrove sediments. Armandeh et al., (2022) isolated 11 isolates belonging to Pseudomonas and Acinetobacter from the sediments of aquaculture pond.
 

Table 2: Details of the identified PSB isolates from sediment samples.


 
Measurement of P- solubilizing efficiency of PSB isolates in solid medium
 
Maximum clear zone of 9 mm thickness observed in B. altitudinis. Rhodococcus sp and Arthrobacter sp showed 4 mm thickness of clear zone. Though the clear zone formation of other isolates such as B. aryabhattai and B. paramycoides were lower than that of B. altitudinis, the solubilizing activity in liquid media was comparatively high.
       
The PSB isolates that produced very mild clear zones on solid medium, could also solubilize various types of insoluble inorganic phosphate in liquid medium (Das, 1963). This may be because of varying diffusion rates of different organic acids secreted by an organism (Johnson, 1959). Many researchers (El-Tarabily et al., 2008; Park et al., 2012) reported that the P-solubilization by bacterial inoculation results in drop in pH of culture media, which facilitate transformation of insoluble-P into soluble-P (Selvi et al., 2017; Behera et al., 2017a). In the present study on P - solubilizing efficiency, the liquid medium showed a reduction in pH (7.0 to 4.2) within 3 days of incubation. The reduction in pH of culture media is associated with the production of different organic acids.
 
P-solubilizing activity and ACPase activity of PSB isolates in liquid medium
 
The ACPase activity and P-Solubilizing activity of PSB isolates in broth after 48 h of incubation is shown in Fig 2 and 3. The ACPase activity of isolates ranged from 4.40±0.28 -22.77±0.32 mmol ml-1 h-1. Arthrobacter sp exhibited maximum ACPase activity (22.77±0.32 mmol/ml/h) followed by Rhodococcus sp (18.08±0.71mmol ml-1 h-1), B. altitudinis (16.31±0.71 mmol ml-1 h-1). The P solubilizing activity and P solubilizing rate in liquid medium observed in the isolates ranged from 7.62±0.51- 16.33±0.84 mg/l and 0.11-0.22 mgl-1 h-1 in 72 h of incubation respectively.
 

Fig 2: ACPase activity of PSB isolates.


 

Fig 3: P- solubilizing activity of PSB isolates Arthrobacter sp.


       
Kathiresan and Selvam (2006) reported that phosphate solubilizing efficiency of 24 isolates from Vellar estuary at Parangipettai, Tamil Nadu was in the range of 0.012-0.141 mg/l. Vibrio sp and Pseudomonas sp from the marine sediment reported to solubilize 0.5-0.55 mg/l (Promod and Dhevendaran, 1987). Bacterial species such as B. subtilis, Pseudomonas sp and Azotobacter sp isolated from mangrove sediment of Chollangi, East Godavari, exhibited a P-solubilising ability in the range of 80-100 mg/l (Audipudi et al., 2012).  Much higher phosphate solubilising activity (400 mg/l) was also reported in the bacterial population from the arid mangrove ecosystem in Mexico (Vaquez et al., 2000). Behera et al., (2017a) documented that Serratia sp. isolated from mangrove soil of Mahanadi River delta showed P-solubilizing activity of 44.84 mg/ml, accompanied by a decrease in pH of the growth medium from 7.0 to 3.15.
 
Production of organic acids by PSB isolates from sediment samples
 
The organic acids produced by the selected PSB isolates (B. altitudinis, Arthrobacter sp and Rhodococcus sp) were shown in Fig 4. HPLC analysis of organic acids revealed that B. altitudinis produced 66.53 mg/kg of lactic acid, 37.8 mg/kg of acetic acid, 20.21 mg/kg of citric acid, 18.89 mg/kg of succinic acid and 15.1 mg/kg of oxalic acid; Arthrobacter sp produced 320.62 mg/kg of acetic acid, 35.36mg/kg of oxalic acid and 14.07 mg/kg of citric acid; Rhodococcus sp produced relatively very low quantity of citric acid (3.94 mg/kg), lactic acid (4.03 mg/kg) and oxalic acid (3.95 mg/kg).
 

Fig 4: HPLC analysis of organic acids.


       
The organic acids solubilize P by chelating metals ions that would immobilize it or forming soluble complexes with P via metal ions or both (Neumann et al., 2000). The P-solubilization rate depends not only on the pH reduction of culture media, but also on the structure and type of the organic molecule produced and not the concentration of organic acid (Johnston, 1952). It is reported that oxalic, 2-ketogluconic and succinic acids produced by Bacillus sp have the capability to solubilize P (Banik and Dey, 1983). Park et al., (2009) documented that Pseudomonas fluorescens produced oxalic, trans-aconitic, citric, tartaric, malic, gluconic, succinic and fumaric acids; Pantoea sp and Enterobacter sp produced lactic, acetic, propionic, pyruvic, malonic, maleatic, tartaratic, oxalic, succinic, fumaric, citric and trans-aconitic acids to solubilize the inorganic P respectively. The P solubilisation activity of Alcaligenes faecalis decreased in pH levels 7.0 to 3.2 of the growth medium with the production of organic acids such as oxalic acid, citric acid, malic acid, succinic acid and acetic acid (Behera et al., 2017b). 
 
Microcosm experiment with PSB isolates
 
The P-mobilizing potential of the PSB isolates obtained in this study were compared with the commercial P biofertilizer following a microcosm study. The initial water quality parameters in the microcosm study were pH-8.2; alkalinity-160 mg/l; salinity-35ppt; ammonia-0.017mg/l; phosphorus-0.31 mg/l. And the initial sediment characteristics such as pH, EC, Available-P, Total -P are given in Table 3. Fig 5 shows the phosphate in water and ALP activity and available-P in the sediment during microcosm experiment for PSB isolates. The control tank showed stable available-P (48.10-52.31 ppm) and ACPase activity (17.86-20.80 mmol/g/h) in sediment and orthophosphate (3.07-3.17 mg/l) in water from 0-21 days. The tanks inoculated with B. altitudinis, Rhodococcus sp, Arthrobacter sp and commercial product showed significant increase in ACPase activity and available-P in sediment and orthophosphate in water from 2nd day onwards. The ACPase activity of the sediment was found to be higher in the tank inoculated with Rhodococcus sp (12.00 mmolg-1h-1) followed by commercial product (11.23 mmol g-1 h-1), B. altitudinis (10.03 mmol g-1 h-1) and Arthrobacter sp (8.10 mmol g-1 h-1). The available P of the sediment on 21st day was in the following order: Commercial product (128.25 ppm) > Rhodococcus sp (110.2 ppm) > B. altitudinis (85.77 ppm) > Arthrobacter sp (82.65 ppm). The phosphate level in the water of microcosm study on 21st day was observed in the following order: Rhodococcus sp and commercial product (0.49 mg/l) > B. altitudinis (0.46 mg/l) > Arthrobacter sp (0.417 mg/l). With regard to phosphate level in the water, there is no significant difference observed between Rhodococcus sp and commercial product. The initial and final PSB count in water samples of treatment tanks during the study period were in the range of 2-3 CFU/ml and 26-42 CFU/ml. The initial and final PSB count in soil samples of treatment tanks during the study period were in the range of 5-7 CFU/g and 1-3´103 CFU/g. In the present study, water-P, ACPase activity and available-P of sediment were increased up to 0.32-0.53 times, 0.56-1.16 times and 0.58-1.45 times respectively. This study gives evidence that apart from Bacillus sp, Rhodococcus sp and Arthrobacter sp could be used as biofertilizer in aquaculture.

Table 3: Physico-chemical characteristics of sediment in microcosm set up of PSB isolates.


       

Fig 5: Available-P and ACPase activity in sediment and Phosphate in water of microcosm experiment.


 
Microcosm study with PSB isolates of Vovk et al., (2013), was similar to the present study, where they warranted that application of Paenibacillus polymyxa contributes to an increase in mineral phosphorus in pond water by 1.3-3.7 times compared to the control. It was carried out in a 30 L tank consisting of pond water with concentration of PSB, Paenibacillus polymyxa KB (4.50±0.50) × 102 - (5.63±0.46) × 103 CFU/ml for 35 days.  They also inferred that introducing bacterial fertilizer on the floor increased the mineral phosphorus content in the aquatic environment more rapidly (15-17 days) than introducing it on the water surface (25-30 days). Similarly, the study of Zhou et al., (2023) revealed that application of B. cereus mutant strain S458-M in Crucian carp culture systems improved the concentration of phosphorus in aquaculture water. Further studies are needed to evaluate the rate of application based on soil texture, organic carbon and total phosphorus.
This study describes the isolation, characterization and identification of PSB bacteria from rhizospheric sediments of A. marina from the Ennore region. As the study region belongs to the brackishwater category, the saline tolerant bacteria were isolated which are able to work at salinity conditions. Further, this study provides evidence for application of Rhodococcus sp and Arthrobacter sp as biofertilizers in aquaculture systems too. Knowledge on mineralizing potential of the native bacterial isolates of Bacillus sp, Rhodococcus sp and Arthrobacter sp with respect to various environmental parameters will be helpful in the development of management activities utilizing these isolates in aquaculture application.
I thank Dean, Dr MGR Fisheries College and Research Institute, TNJFU, Ponneri for providing the necessary support and facilities for carrying out this work.
All authors declared that there is no conflict of interest.

  1. Alori, E.T., Glick, B.R. and Babalola, O.O. (2017). Microbial phosphorus solubilization and its potential for use in sustainable agriculture. Front. Microbiol. 8: 971. 

  2. Amutha, R., Karunakaran, S., Dhanasekaran, S., Hemalatha, K., Monika, R., Shanmugapriya, P. and Sornalatha, T. (2014). Isolation and Mass Production of Biofertilizer (Azotobacter and Phosphobacter). IJLRST. 3(1): 79-81.

  3. Armandeh, M., Mahmoudi, N. and Nosratabad, A.R.F. (2022). Screening and evaluation of phosphate solubilizing bacteria isolated from aquaculture ponds in a step by step strategy as potential biofertilizer. J. Appl. Microbiol. 133(3): 1581-1596.

  4. Aruna, B. and Jain, D. (2021). Isolation, characterization of phosphatase producing bacteria and fungi- Their effect on enhancing the growth of Vigna radiate. Indian J. Agric. Res. 55: 396-402.

  5. Aruna, S., Manikandavelu, D., Uma, A., Cheryl Antony and Jayakumar, N. (2023). Assessment of phosphorus mobilizing capacity of Bacillus spp. isolated from mangrove Rhizospheric sediment and its potential application in Aquaculture. Indian Journal of Animal Research. DOI: 10.18805/IJAR.B-5172.

  6. Audipudi, A.V., Kumar, P. and Sudhir, A. (2012). Phosphate Solubilizing Microorganisms Associated with Chollangi Mangrove Soil in East Coast of India. Int. J. Sci. Eng. Res. 3(11): 2229-5518.

  7. Banik, S. and Dey, B.K. (1983). Phosphate solubilizing potentiality of the microorganisms capable of utilizing aluminium phosphate a sole phosphate source. Zentralbl. Mikrobiol. 138: 17-23.

  8. Behera, B.C., Yadav, H., Singh, S.K., Mishra, R.R., Sethi, B.K., Dutta, S.K. and Thatoi, H.N. (2017a). Phosphate solubilization and acid phosphatase activity of Serratia sp. isolated from mangrove soil of Mahanadi River delta, Odisha, India. J. Genet. Eng. Biotechnol. 15(1): 169-178.

  9. Behera, B.C., Yadav, H., Singh, S.K., Mishra, R.R., Sethi, B.K., Mishra, R.R., Kumari, S. and Thatoi, H. (2017b). Alkaline phosphatase activity of a phosphate solubilizing Alcaligenes faecalis, isolated from Mangrove soil. Biotechn. Res. Innov. 1: 101-111.

  10. Cao, Y., Fu, D., Liu, T., Guo, G. and Hu, Z. (2018). Phosphorus solubilizing and releasing bacteria screening from the rhizosphere in a natural wetland. Water. 10: 195.

  11. Das, A.C. (1963). Utilization of insoluble phosphates by soil fungi. J. Indian Soc. Soil Sci. 11: 203-207.

  12. Egamberdieva, D., Wirth, S., Bellingrath-Kimura, S.D., Mishra, J. and Arora, N.K. (2019). Salt-tolerant plant growth promoting rhizobacteria for enhancing crop productivity of saline soils. Front. Microbial. 2791.

  13. El-Tarabily, K.A., Nassar, A.H. and Sivasithamparam, K. (2008). Promotion of growth of bean (Phaseolus vulgaris L.) in a calcareous soil by a phosphate-solubilizing, rhizosphere competent isolate of Micromonospora endolithica. Appl. Soil Ecol. 39: 161-171.

  14. Garcia-Fraile, P., Menendez, E., Celador- Lera, L., Diez-Mendez, A., Jimenez-Gomez, A., Marcos-Garcia, M., Cruz-Gonzalez, X.A., Martinez-Hidalgo, P., Mateos, P.F. and Rivas, R. (2017). Bacterial probiotics: A truly green revolution. In Probiotics and plant health Springer, Singapore, 131 -162.

  15. Ghaderi, A., Aliasgharzad, N., Oustan, S. and Olsson, P.A. (2008). Efficiency of three Pseudomonas isolates in releasing phosphate from an artificial variable-charge mineral (iron III hydroxide). Soil Environ. 27: 71-76.

  16. Iwaoka, C., Imada, S., Taniguchi, T., Du, S., Yamanaka, N. and Tateno, R. (2018). The impacts of soil fertility and salinity on soil nitrogen dynamics mediated by the soil microbial community beneath the halophytic shrub tamarisk. Microb. Ecol. 75(4): 985-996.

  17. Johnson, H.W. (1959). The solubilisation of insoluble phosphate IV there action between organic acids and tricalcium phosphate. N.Z. J. Sci. 2: 215-218.

  18. Johnston, H.W. (1952). The solubilization of phosphate. I. The action of various organic compounds on dicalcium and tricalcium phosphates. NZ. J. Sci. Technol. 436-446.

  19. Kalayu, G. (2019). Phosphate solubilizing microorganisms: promising approach as biofertilizers. Int. J. Agron. 4917256.

  20. Kathiresan, K. and Selvam, M.M. (2006). Evaluation of beneficial bacteria from mangrove soil. Botanica Marina. 49: 86-88.

  21. Neumann, G., Massonneau, A., Langlade, N., Dinkelaker, B., Hengeler, C., Romheld, V. and Martinoia, E. (2000). Physiological aspects of cluster root and development in phosphorus- deficient white lupins. Ann. Bot. 85: 909-919.

  22. Park, J., Bolan, N., Megharaj, M. and Naidu, R. (2012). Isolation of phosphate-solubilizing bacteria and characterization of their effects on Lead immobilization. Pedologist. 67-75.

  23. Park, K.H., Lee, C.Y. and Son, H.J. (2009). Mechanism of insoluble phosphate solubilization by Pseudomonas fluorescens isolated from rhizosphere and its plant growth-promoting activities. Lett. Appl. Microbiol. 49: 222-228.

  24. Promod, K.C. and Dhevendaran, K. (1987). Studies on phosphobacteria in Cochin backwater. J. Mar. Biol. Assoc. India. 29: 297-305.

  25. Ravikumar, S., Jacob Inbaneson, S., Seshserebiah, J. (2009). Cadmium induced effect on growth and physiology in halophilic phosphobacteria. J. Environ. Biol. 30(5): 673-676.

  26. Selvi, K.B., Paul, J.J.A., Vijaya, V. and Saraswathi, K. (2017). Analyzing the efficacy of phosphate solubilizing microorganisms by enrichment culture techniques. Biochem. Mol. Biol. J. 3(1): 1-7.

  27. Sundara, B., Natarajan, V. and Hari, K. (2002). Influence of phosphorus solubilizing bacteria on the changes in soil available phosphorus and sugarcane yields. Field Crops Res. 77: 43-49.

  28. Tabatabi, M.A., Bremner, J.M. (1969). Use of P-nitrophenyl phosphate for assay of soil phosphatase activity. Soil Biol. and Biochem. 1: 301-307.

  29. Vazquez, P., Holguin, G., Puente, M., Lopez-cortes, A. and Bashan, Y. (2000). Phosphate solubilizing microorganisms associated with the rhizosphere of mangroves in a semi-arid coastal lagoon. Biol. Fertil. Soils. 30: 460-468.

  30. Vovk, N.I., Bazaeva, A.V. and Didenko, A.V. (2013). Use of the phosphate-solubilizing bacterial preparation polymyxobacterin in pond aquaculture. Turkish J. Fish. Aquat. Sci. 13: 01-09.

  31. Weisburg , W.G., Barns, S.M., Pelletier, D.A. and Lane, D.J. (1991). 16S ribosomal DNA amplification for phylogenetic study. J. Bacteriol. 173(2): 697-703. doi: 10.1128/jb.173.2.697- 703.1991.

  32. Yadav, H., Gothwal, R.K., Nigam, V.K., Sinha-Roy, S. and Ghosh, P. (2013). Optimization of culture conditions for phosphate solubilization by a thermo-tolerant phosphate-solubilizing bacterium Brevibacillus sp. BISR-HY65 isolated from phosphate mines. Bio-catal. Agric. Biotechnol. 2: 217-225.

  33. Zhang, J., Han, L., Ji, Y., Duan, M., Cai, G., Wu, J., Zhu, W., Gao, G., Peng, Y. and Zhou, Y. (2018). Study of soil nutrients, physical and biological characteristics of paddy fields after lifting measures: A case study of China’s Ganjiang region. J. Environ. Biol. 39: 432-439.

  34. Zhou, X., Yang, Q., Long, K., Tang, X., Luo, L., Wu and Li, Y. (2023). Effect of Bacillus cereus mutant strain S458-M on active phosphorus and Crucian carp in culture systems. Aquaculture 573. doi.org/10.1016/j.aquaculture.2023.739627.

Editorial Board

View all (0)