Could Amino Acids Produced by Bacteria Be Used as An Alternative Source of Nitrogen Fertilizer in Corchorus olitorius L.

Abstract

A laboratory experiment followed by field experiment were conducted during 2014 and 2015 seasons to find the answer for; could amino acids (AA) produced by bacteria be used as alternative nitrogen fertilizer source. The laboratory experiment was carried out to study the amino acids quantity and quality produced by Bacillus sp. R20EG2 strain using continuous fermentation at different levels of feeding with sugar cane molasses at dilution rates 0.017, 0.027, 0.037 and 0.047 h 1. At 0.037 h 1 dilution rate, the amino acid concentration was increased to reach up to 4.01 g/L after 24 h fermentation time comparing to other dilution rates. Also, amino acid productivity was 0.167 g/L/h which increased from 1.86 to 3.56 fold comparing with batch and fed-batch fermentation from previous study. From qualitative and quantitative estimation of amino acids in the supernatant, the highest amounts were for glutamic and aspartic acids. Therefore, the produced AA fermented solution combined with different concentrations of urea as a mineral nitrogen source were tested in a field experiment on Jew's mallow plant. AA concentrations at 0, 250, 500, 1000 and 2000 ppm were applied to the foliar system, whereas urea was added to the soil with the following levels 0, 35 and 70 kg/feddan (recommended dose). Individual foliar applications of AA fermented solution over 250 ppm led to an increase in most of studied vegetative parameters over the recommended dose of urea, especially for average leaf f.w and plant f.w, which reflected on increasing the yield of both leaves and entire plant, respectively. The highest values in all vegetative parameters and biochemical content per leaf unit except for nitrate content were recorded with AA treatment at 500 ppm combined with all levels of urea. Although, the highest significant values in leaves yield recorded with treatments of AA at 500 ppm and AA at 500 ppm + urea at 70 kg/feddan, the highest significant values for entire plant yield recorded with the combined applications of AA at 500 ppm with urea at 70 & 35 kg/feddan followed by individual treatment of AA at 500 ppm. AA individual treatments reduced the content of nitrate in leaves of Jew's mallow plants.