Silicate Solubilizing Bacteria

Silicate solubilizing bacteria (SSB)

Microorganisms are able to degrade silicates and aluminum silicates. In the course of the metabolism of microbes numerous organic acids are produced and those have a twin position in silicate weathering. They supply H+ ions to the medium and promote hydrolysis and the natural acids like citric, oxalic acid, Keto acids, and hydroxy carbolic acids which form complexes with cations, promote their elimination and retention within the medium in a dissolved state.

The studies performed with a Bacillus sp. cultured from the soil of granite crusher yard confirmed that the bacterium is capable of dissolving numerous silicate minerals beneath in vitro situation. The exam of anthropogenic substances like cement, agro inputs like incredible phosphate and rock phosphate exhibited silicate solubilizing bacteria to a varying diploma. The bacterial isolates crafted from distinctive places had various degree of silicate solubilizing potential. Soil inoculation research with decided on isolated with red soil, clay soil, sand and hilly soil showed that the organisms elevated in all forms of soil and released greater of silica and the available silica expanded in soil and water. Rice replied nicely to a utility of natural siliceous residue like rice straw, rice husk, and black ash. Combining SSB with these residues, in addition, led to improved plant growth and grain yield. This enhancement is because of elevated dissolution of silica and nutrients from the soil.

Plant growth promoting Rhizobacteria (PGPR)

The group of microorganism that colonizes roots or rhizosphere soil and useful to crops is known as plant growth promoting rhizobacteria (PGPR).

The PGPR inoculants currently commercialized that seem to promote growth through at the least one mechanism; suppression of plant disease (termed Bioprotectants), improved nutrient acquisition (termed Biofertilizers), or phytohormone production (termed Biostimulants). Species of Pseudomonas and Bacillus can produce as but now not well-characterised phytohormones or growth regulators that motive crops to have extra amounts of pleasant roots which have the impact of growing the absorptive surface of plant roots for uptake of water and nutrients. These PGPR are referred to as Biostimulants and the phytohormones they produce encompass indole-acetic acid, cytokinins, gibberellins and inhibitors of ethylene production.

Current advances in molecular techniques are also encouraging in that gear are becoming to be had to decide the mechanism by way of which crop performance is stepped forward the use of PGPR and track survival and pastime of PGPR organisms in soil and roots. The technology of PGPR is on the level in which genetically modified PGPR can be produced. PGPR with antibiotic, phytohormone and siderophore manufacturing can be made.

Despite promising effects, biofertilizers have not were given substantial utility in agriculture especially due to the variable response of plant species or genotypes to inoculation relying on the bacterial strain used. Differential rhizosphere effect of plants in harbouring a target stress or even the modulation of the bacterial nitrogen fixing and phosphate solubilizing capacity through unique root exudates might also account for the determined differences. Alternatively, right aggressive capacity and excessive saprophytic competence are the foremost factors figuring out the fulfillment of a bacterial stress as an inoculant.

Research to recognise the synergistic activities and endurance of precise microbial populations in complex environments, such as the rhizosphere, have to be addressed with the intention to attain green inoculants. In this regards, research efforts are made at Agricultural college and research Institute, Madurai to acquire suitable formulations of microbial inoculants incorporating nitrogen-fixing, phosphate- and silicate- solubilizing bacteria and plant growth promoting rhizobacteria for people to help in promoting the use of such beneficial bacteria in sustainable agriculture.

Liquid Biofertilizers

Biofertilizers are such as Rhizobium, Azospirillum and Phosphobacteria offer nitrogen and phosphorous nutrients to crop plant life via nitrogen fixation and phosphorus solubilization techniques. These Biofertilizers may be efficaciously utilized for rice, pulses, millets, cotton, sugarcane, vegetable and different horticulture plants.

Biofertilizers are one of the top centers in organic farming, not most effective complements the crop growth and yield, however, additionally improves the soil health and maintain soil fertility.

At present, Biofertilizers are provided to the farmers as the carrier based totally inoculants. As an alternative, liquid formula technology has been developed within the branch of Agricultural Microbiology, TNAU, Coimbatore which has more blessings than the provider inoculants.

Advantages

The advantages of Liquid Bio-fertilizer over conventional carrier-based totally Bio-fertilizers are indexed under:

• Longer shelf lifestyles 12-24 months.
• No contamination.
• No loss of properties because of storage up to forty fiveº c.
• Greater potentials to combat with native populace.
• High populations can be maintained greater than 109 cells/ml up to 365 days to 24 months.
• Clean identity with the aid of traditional fermented scent.
• Cost saving on service cloth, pulverization, neutralization, sterilization, packing, and transport.
• Best manage protocols are smooth and short.
• Better survival on seeds and soil.
• No need of jogging Bio-fertilizer manufacturing devices throughout the year.
• Very plenty clean to apply through the farmer.
• Dosages are 10 times much less than carrier based totally powder Bio-fertilizers.
• High industrial revenues.
• High export ability.
• Very high enzymatic activity given that contamination is nil.

Characteristics of various liquid Bio-fertilizers

Rhizobium

This belongs to the bacterial organization and the classical instance is symbiotic nitrogen fixation. The microorganism infects the legume root and shapes root nodules within which they reduce molecular nitrogen to ammonia that is reality used by the plant to provide precious proteins, nutrients, and different nitrogen-containing compounds. The site of symbiosis is within the root nodules. it's been envisioned that 40-250 kg N / ha / yr is constant by one of a kind legume crops by means of the microbial activities of Rhizobium. The percentage of nodules bodily capabilities of liquid Rhizobium

• White in colour
• No horrific smell
• No foam formation, pH 6.8-7.5

Azospirllium

It belongs to bacteria and is thought to repair the good sized amount of nitrogen in the range of 20- 40 kg N/ha within the rhizosphere of non-leguminous plants such as cereals, millets, Oilseeds, cotton etc. The efficiency of Azospirillium as a Bio-Fertilizer has increased due to its ability to induce ample roots in numerous pants like rice, millets, and oilseeds even in upland conditions. The vast quantity of nitrogen fertilizer up to 25-30 % may be saved by means of using Azospirilluminoculant. The genus Azospirillum has three species viz., A. lipo forum, A. brasilence and A. amazonense. Those species have been commercially exploited for the use as nitrogen offering Bio-Fertilizers.

One of the traits of Azospirillum is its potential to reduce nitrate and denitrify. Each A. lipoferum and A. brasilense may also include of lines that could actively or weakly denitrify or lessen nitrate to nitrite and consequently, for inoculation coaching, it is vital to select strains which do not possess those traits.Azospirllium lipoferum present within the roots of a number of tropical forage grasses such as Digitaria, Panicum, Brachiaria, Maize, Sorghum, Wheat, and Rye.

Physical functions of liquid Azospirillum

• The colour of the liquid can be blue or white.
• Terrible odours confirm unsuitable liquid formula and can be concluded as mere broth.
• Manufacturing of yellow gummy coloration substances confirms the first-class product.
• Acidic pH continually confirms that there are no Azospirillum bacteria inside the liquid.

Production of growth hormones

Azospirillum cultures synthesize the large quantity of biologically energetic materials like nutrients, nicotinic acid, indole acetic acids fibrillins. Most of these hormones/chemical substances facilitate the plants in better germination, early emergence, better root development.

References

Cassida, L.E Jr.Industrial microbiology.New age into publishers, 1996.

I, Stever.Biochemistry.new york Wall freeman company, 1995.

JE, Smith.Biotechnology.Sinauer Association, 2000.

Nelson, D L and M M Cox.Leininger Principle of Biochemistry.Fifth. Freeman publication, 2004.