Isolation and identification of microorganism from polyhouse agriculture soil of Rajasthan

The present work deals with the isolation and characterization of microorganisms from polyhouse agriculture soil of Jharna village (Rajasthan). Several bacteria and fungi were isolated from polyhouse soil, using serial dilution method. These bacterial isolates were Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterobacter aerogenes, Shigella sp., Proteus mirabilis, Bacillus anthracis, Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis species which were further identified on the basis of colony morphology, Gram staining, biochemical tests and using selective and differential media. Identification of fungi such as Aspergillus niger, Aspergillus flavus, Fusarium oxysporum, Trichoderma sp. and Rhizopus sp. was carried out by culturing on potato dextrose and sabouraud’s dextrose agar media and microscopic method. Microorganisms play an important function in biodegradation of solid agriculture waste and also help in the crop production.


INTRODUCTION
Microorganism are frequently present in soil, manure and decaying plant tissues which are able to degrade wastes that are correlated with the substrate organic matter (Alexander, 1977).Agriculture soil is a dynamic medium in which a large number of pathogenic and non-pathogenic bacterial and fungal flora live in close association.Microbes in the soil are the key to carbon and nitrogen recycling.Microorganisms produce some useful compounds that are beneficial to soil health, plant growth and play an important role in nutritional chains that are important part of the biological balance in the life in our planet (Paul and Clerk, 1966;Kummerer, 2004).Polyhouses are basically naturally ventilated climate controlled.Poly-house cultivation has been evolved to create favorable micro-climates, which favours the crop production and could be possible all through the year or part of the year as required.Wherein, off season crops are also grown under a favorable controlled environment and other conditions viz.temperature, humidity, light intensity, ventilation, soil media, irrigation, fertigation and other agronomical practices throughout the season irrespective of the natural conditions outside.Therefore, the soil of polyhouse may have different conditions for growth of microorganism than natural environment.The present study aimed to isolate effective microorganisms that are present in polyhouse soil and find out the optimize culture conditions.

Collection of soil samples
Agricultural soil sample were collected from polyhouse of Jayoti Vidyapeeth Women's University campus, located at East Longitude-75° 27' 38", North Latitude-26° 49' 34", 450-500 m above sea level, weather: Temperature -28-34° C in summer, 12°-18° C in winter, Jaipur, Rajasthan (Figure 1).Soil samples were taken with the help of sterile spatula, in sterile plastic bags.The samples were brought to the microbiology laboratory.

Determination of physiochemical properties of soil
Freshly collected soil samples were taken for determination of physiochemical properties.The moisture content of the sample was measured in a hot air incubator at 105°C to constant weight.The pH, temperature, humidity, and air pressure was determined using digital pH meter, thermometer, hygrometer and barometer, respectively (Pramer and Schmidt, 1964;Iyengar and Bhave, 2005).

Isolation of microorganism
The microorganisms were isolated by serial dilution technique on Potato Dextrose Agar (PDA) and Nutrient Agar Media (NAM).In this technique, a sample suspension was prepared by adding 1.0 g sample to 10 ml distilled water and mixed well for 15 min and vortexed.Each suspension was serially diluted 10 -1 to 10 -6 .0.1 ml was pipetted onto plates with PDA and NAM media, spread with a glass spreader and incubated at 28°C for fungal and 37°C for bacterial observation.Each colony that appeared on the plate was considered as one colony forming unit (cfu) (Waksman, 1927;Nazir, 2007).

Identification of fungi
The fungal isolates were identified by morphological examination and its characteristics.Morphological characteristics were examined under microscope (Onion et al., 1981).

Optimization of culture condition for fungi
For the determination of optimum condition of isolated fungi, three media were used (Potato dextrose agar media, Sabouraud's dex-trose agar, Czapack Dox agar).The media were adjusted to pH 4 to 7. For optimization of the incubation period, the culture plates were incubated at 28°C for 4 to 7 days (Bhattacharyya and Jha, 2011;Azzaz et al., 2012).

Identification and characterization of Bacteria
Gram staining was performed to check the morphology of the cells and spore chain morphology was identified by spore staining technique.The pure culture was grown on nutrient agar medium and transferred to Mac-conkey agar medium, EMB agar medium, Endo-Agar medium and mannitol salt agar medium for differentiate and identified bacteria The plates were incubated at 37°C in the incubator and readings were taken 24 h after inoculation.The bacterial isolates were biochemically characterized by catalase test, oxidase test, urease test, motility test, TSI test, nitrate reduction test and IMVIC test (Collins and Lyne, 1989;Harold, 2002;Zaved et al., 2008).

RESULTS AND DISCUSSION
This study revealed that polyhouse soil samples were analyzed with respect to different types of bacteria and fungi.1).
In the present study, the isolated fungi were identified on the basis of cultural, microscopic and morphological characteristics (Figure 2).Earlier work reported that for maximum growth of fungi, potato dextrose agar was most favorable (Maheshwari, 2000).The isolated fungi were  cultured in PDA, SDA and Czapeck Dox agar media.It was observed that the PDA and SDA media were most suitable for good growth of A. niger, A. flavus and Trichoderma sp., Rhizopus sp. and Fusarium oxysporum at optimum range of pH 6 to 8 and a suitable incubation period was 4 to 7 days, respectively.However, czapeck dox agar medium was also suitable for A. niger, A. flavus, Trichoderma sp., Rhizopus sp. and F. oxysporum.Most of the fungi show favorable growth in alkaline side of neutral pH but they can also tolerate the pH range from 6 to 8 (acidic to basic) (Table 2).The enzymatic activities and use of bacteria, actinomycetes and fungi in the decomposition of organic matter provides beneficial metabolic products to the soil (Tiquia et al., 2002;Singh et al., 2003).Similarly, Karthik et al. (2011) also reported the isolation, identification of microorganisms such as Bacillus species from agricultural waste dump soil for screening of pectinase producing activity.The isolation of various fungal, bacterial species showed that the agricul-tural soil is quite rich in microbial flora.In agriculture process, soil microorganisms such as bacteria and fungi may play important roles in soil fertility and in the form of loss and gain in the production of grains, fruits, vegetables.Moreover, it also helps to maintain or enhance the environment quality and conserve natural resources.Most of the bacteria such as Bacillus anthracis, B. subtilis, and S. aureus and S. epidermidis isolated in this study have been reported by other researchers (Amir and Pineau, 1998;Okoh et al., 1999).Several bacteria were isolated from agriculture soil samples.Identification and characterization of isolated bacteria were performed by morphological, microscopically (Figure 3), biochemical tests such as shape, arrangement, colonies, temperature, growth, indole production test, ethyl red and Vogesproskauer test, citrate utilization test, urease test, catalase test, Mac-conkey's test, TSI test, growth at 37°C (Table 3).Further, selective and differentiate media were prepared and the isolated bacteria were inoculated under sterilized conditions incubated at 37°C for 18 to 24 h and the results were recorded (Table 4).In different fermentation media, isolates showed different level of growth.The growth of S. aureus was observed on mannitol salt agar medium.In the presence of high salt concentration, S. aureus fermented mannitol producing acid which changes the pH turning phenol red to yellow (Figure 4).The present study, concluded on isolation and identification of bacterial and fungal floras with optimum pH, temperature and other cultural condition.These isolated polyhouse soil bacteria and fungi are also used in the seasonal and off season crop production with different environment condition.These microorganisms are to supply nutrients to crop, to encourage plant growth; for example, through the production of plant hormones and to control or inhibit the activity of plant pathogen.This study provides knowledge on microorganisms of Rajasthan semi arid soil which is used in polyhouse and produce seasonal and off seasonfoods and vegetables which are not able to grow in normal environment condition.

Conclusion
The environment where we live is the habitat for various microorganisms; mostly bacteria and fungi which are used for various industrial applications like enzymes production, fabric manufacturing, bioremediation, pharmaceutical production, etc. Micro-organisms play an important role in composting of organic waste and can be an important contributor to optimal agricultural waste.This study revealed the isolation and identification of diversity of microorganisms which are present in agricultural soil habitat.

Table 1 .
Physiochemical properties of soil samples.

Table 2 .
Effect of pH and incubation period on the growth of isolated fungi on PDA, SDA, Czapek -Dox agar media at 28°C temperature.

Table 3 .
Biochemical characterization of bacterial isolates.

Table 4 .
Growth of bacterial isolates on different media.