|Authors: ||Z.T. Daza, A. Gallo, L.M. Rincón, D.S. Parrado, M.C. Santander, A. Oviedo, H. Chica, M.M. Martínez S.|
|Keywords: ||compost, hydrolytic enzymes, Bacillus sp. bioaugmentation|
The production of sugar, ethanol and electricity from sugarcane generates by-products such as leaves, bagasse, muds, ash and vinasse that are transformed through composting processes, where the enzymatic activity of microorganisms, promotes the mineralization of organic materials.
These microorganisms can be enhanced for their biotechnological use in biodegradation processes of organic matter.
The present research aimed to isolate and select microorganisms with enzymatic activity from compost piles and to produce a bio-inoculant with hydrolytic activity.
By enzymatic activity tests, six bacterial strains were isolated, and characterized using BIOLOG®. Amylolytic, cellulolytic and proteolytic enzymatic activities were evaluated in chemically defined media, incubated at 150 rpm and 37 and 55°C for 48 h.
Activity was quantified by 3,5-dinitrosalicylic acid (DNS) and trichloroacetic acid (TCA) techniques.
Finally, for the production test of microbial culture, a non-commercial medium with vinasse and molasses was used in a BioFlo® 110 bioreactor.
The results showed that microorganisms produced amylases, cellulases, lipases and proteases as hydrolytic enzymes both at mesophilic temperatures and under thermophilic conditions with higher expression at 24 h of incubation (p=0.025). Strain P1C, identified as Bacillus racemilacticus, presented significantly higher enzyme activities, with 457.20 amylolytic units, 135 cellulolytic units and 298 proteolytic units min-1 L‑1 (α=0.05). In mixed culture, the microbial growth followed a Gaussian model, where the higher amylolytic activity was expressed at 15 h with 365 amylolytic units min-1 and maximum biomass of 1×1010 CFU mL-1.
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