Biotransformation of 5-hydroxymethylfurfural and furfural with bacteria of bacillus genus

Abstract

Furfural and 5-hydroxymethylfurfural (5-HMF) are considered to be the most toxic compounds among fermentation inhibitors in lignocellulosic hydrolysates. These compounds raise severe problems for the bioproduction of fuels and chemicals. In this study, we describe the detoxification of furfural and 5-HMF using bacterial isolates from residues of sugarcane bagasse, identified as Bacillus pasteuri, Bacillus toyonensis, Bacillus megaterium, Bacillus cereus, Bacillus subtilis, and Bacillus spp. by 16S rDNA sequencing. Under aerobic culture conditions, 2-furoic acid and 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) were produced as the main degradation product in the detoxification of furfural and 5-HMF, respectively. In both cases these acids were produced in greater concentrations when bacteria were incubated in nutrient broth. B. toyonensis in nutrient broth with 20 mM of furfural after 120 h produced the highest amount of 2-furoic acid. A concentration of 15.2 mM was achieved using B. toyonensis followed by B. cereus with a concentration of 13.1 mM 2-Furoic acid production for other strains did not exceed 6.8 mM. B. toyonensis was the strain with highest degradation capacity of 5-HMF, following the oxidation pathway to obtain HMFCA and 2,5-furan dicarboxylic acid (FDCA) which rose to a final concentration of 21.3 mM and 1.5 mM, respectively, in a nutrient broth with 25 mM of 5-HMF at 120 h of fermentation. B. toyonensis is a useful strain to detoxify lignocellulosic residues and to produce furans with a high added value. • First comparative study of strains belonging to genus Bacillus in the biotransformation of furans. • First study on B. pasteuri and B. toyonensis used in the biodegradation of furfural and 5-HMF. • The novel B. toyonensis is a native strain that is highly tolerant to 5-HMF/furfural (>60 mM) with the ability to produce 2-furoic acid and HMFCA in nutrient broths with yields greater than 76 and 85%, respectively.