Plant growth promoting activity of keratin degrading Bacillus cereus. Prasad Memane Department of Microbiology, Modern College of Arts, Commerce and Science, Ganeshkhind, Pune-16 prasadmemane10@gmail.com@gmail.com
Background- Keratin is one of the major structural protein present in animals. Many industrial processes such as poultry, leather, meat processing releases large amount of keratinous waste products in to the environment. Owing to numerous disulfide linkages, hydrogen bonds, hydrophobic interactions and tightly packed peptide chains, keratin is resistant to common biodegradation processes. Rotationalekeratinous waste accumulates in huge volumes causing damage to the environment and human health. However, keratin being proteinaceous in nature, the essential amino acids present in them can be useful in many biotechnological processes. StrategyThe present investigation was carried out with the aim of biodegrading chicken feather waste from poultry industry and applying the feather hydrolysate in agriculture. ResultsPlant growth promoting activity of feather degrading Bacillus cereus was checked. The ability of the isolate to produce indole acetic acid (IAA), siderophore, phosphate solubilisation and ammonia production were checked. Promising results were obtained for all the activities except phosphate solubilisation. The organism was also able to degrade chitin, the main component of fungal cell wall, so this isolate may have antifungal activity and can be used against plant pathogenic fungi. Thus, in situ degradation of chicken feathers may not only serve as a nitrogenbased fertilizer but also plant growth promotion. Poster Design & Printing by Genigraphics® 800.790.4001
INTRODUCTION
RESULTS
Keratin protein is a tough, fibrous, insoluble and third most important polymer in the environment. Keratin protein belong to scleroprotein group. sources of keratin includes Feathers, animal hooves, horns, wool, scales, nails and hair. Worldwide, around 8.5 billions tons of chicken feathers waste is produced per year. India alone contributes to 350 million tons. It is recalcitrant in nature, causes environmental pollution and adversely affect the people’s health. Hence proper waste management of keratin is necessary. Physical and chemical methods of keratin disposal are available but they are costly and environmentally intensive. Therefore a microbial method for keratin degradation was developed and application of feather hydrolysate as well as feather degrading Bacillus cereus was studied for sustainable agriculture.
Percent degradation-The isolate Bacillus cereus SAS-C degraded 58% chicken feathers within 5 days of incubation at 30°C
MATERIALS AND METHODS Revival and purity checking Chicken feather degrading bacterium was previously isolated and identified as Bacillus cereus SAS-C by MALDI-TOF analysis. Percent feather degradation The minimal feather media were inoculated with the isolate and incubated at 30°. After 5 days the media were filtered out separately and the residue was collected to quantify the percent degradation with the help of total suspended solid method. Siderophore production Siderophore production by the isolate was checked using sterile Chrome azurols agar (CAS) plates with nutrient agar medium. Indole-3-acetic acid (IAA) production Estimation of IAA production by the isolate was checked using Salkowski’s reagent. Ammonia production Qualitative estimation of ammonia by the isolate was checked using Nessler’s reagent Zinc solubilisation activity Zinc solubilization by isolate was checked using sterile Tris-Minimal salt medium. Chitin degradation Chitin degradation by isolate was checked using sterile minimal media with chitin as sole C source Atmospheric nitrogen fixation by isolate Atmospheric nitrogen were checked by growing the isolate on nitrogen free medium. Sterile Ashby’s agar used to grow the isolate. Seed Germination Assay Ten seeds of Vigna radiata (Moong) were placed on filter paper soaked with sterile hydrolysate obtained from the isolate. Sterile distilled water kept as control. Germination was counted at 24 h time interval.
Siderophore production: Siderophores are chelating agents that increase the availability of divalent ions to plants. Orange hallow zone was observed around the colony on CAS agar plate indicating siderophore production by the isolate
IAA production: IAA is known to stimulate increased cell elongation cell division differentiation in plants. Addition of Salkowaski’s reagent resulted in formation of pink colour indicating production of IAA.
Ammonia production: Ammonia production by the bacteria helps influence plant growth indirectly by making nitrogen available in easily assimilated form. Formation of yellowish brown precipitate is considered to be positive test for ammonia production.
Zinc solubilisation: Zinc (Zn) is one of the most important micronutrients required for plant growth and development.. Hence zinc solubilisation ability of the isolate was tested. Zone of clearance was observed around the colony indicating zinc solubilization.
Chitin degradation chitin is the main component of fungal cell wall. Chitin degradation ability can be useful to inhibit fungal pathogens.
Zone of clearance around the colonies after addition of iodine indicate chitinase production by the isolate.
Atmospheric nitrogen fixation Isolate formed colonies on sterile Ashby’s agar medium as seen in the Figure indicating that organism was able to fix atmospheric nitrogen.
Seed Germination Assay Average root length (cm)
ABSTRACT
6 4 2 0 Hydrolysate
Control
Test conditions
As shown in the Figure avaerage root length of the seeds germinated using feather hydrolysate was almost double as compared to the control.
CONCLUSIONS Keratin degrading bacterium shows plant growth promoting as well as chitin degradation activities. Thus in situ degradation of chicken feathers can not only serve as a source of nitrogen based fertilizer but also stimulate plant growth contributing towards sustainable agriculture.
REFERENCES 1. Tamreihao K. Mukherjee S., (2018). Feather degradation by keratinolytic bacteria and biofertilizing potential for sustainable agricultural production. Journal of Basic Microbiology. 59(1):4-13. 2. Joshi S. G., Tejaswini M.M.,Roma D., (2007). Isolation, identification and characterization of a feather degrading bacterium. International Journal of Poultry Science. 6(9): 689-693.