Effect of metabolites obtained from microbial degradation of chicken feathers on lettuce growth

In this study, keratinase-producing bacteria were used to produce natural fertilizer from chicken feathers. Twenty-nine soil samples were collected from 0-30 cm depth of agricultural fields and mixed with chicken feathers. After three weeks, 31 isolates were isolated from the soils mixed with feathers, which were able to grow on the special culture medium of Feather Meal Agar (FMA). The isolates were transferred to a liquid medium containing feathers and their ability to degrade the feathers was investigated. A completely randomized design was used to examine the effect of the solution created by the degradation of chicken feathers on lettuce growth. The experimental treatments included the foliar application of three solutions obtained from the degradation of chicken feathers (gh1, b1, c11), and control (distilled water). The results showed eight isolates were able to completely decompose the feathers in seven days by producing keratinase enzyme. The highest activity of the keratinase enzyme (with the ability to fully degrade the feather: 8.56 U / ml) was related to that of Bacillus methylotrophic strain gh1. Also, the maximum concentration of free amino acid (1065 μg / ml) was observed in the growth medium of Bacillus siamensis strain c11. The three solutions obtained from feather degradation had a significant effect (p < 0.01) on lettuce fresh weight, lettuce dry weight, and fresh root weight. The results showed that the lettuce fresh weight increased by 28.8%, 26.1%, and 14.1%, using Bacillus methylotrophicus (gh1), Bacillus velezensis (b1), and Bacillus siamensis (c11) respectively, compared to the control. In addition, the lettuce dry weight increased by 25.7%, 19.9%, and 15.2%, with the aid of gh1, b1, and c11 treatments, respectively, compared to the control. The results showed that using keratinase-producing bacteria, feather degradation could be increased, and the obtained product can be used as a growth stimulant for lettuce.