Bioconversion of ferulic acid into aroma compounds by newly isolated yeast strains of the Latin American biodiversity

Abstract

Nine yeast strains isolated from Latin American biodiversity were screened for ferulic acid (FA) consumption and conversion into aroma compounds such as vanillin, vanillic acid (VA), and 4-vinylguaiacol (VG). Selected strains (Rhodotorula mucilaginosa UFMG-CM-Y3647, UFMG-CM-Y2190, UFMG-CM-Y665) were evaluated in flask experiments to investigate the influence of the pH media on bioconversion and a two-step process was conducted to maximize the metabolites production. The effect of pH was found to be significantly important for FA bioconversion, as acidic conditions (pH < 6.0) improved VA accumulation, with highest production of 1.14 ± 0.02 and 1.25 ± 0.03 g/L shown by UFMG-CM-Y3647 and UFMG-CM-Y2190, respectively. The two-step process favored 4-VG production for most strains, being UFMG-CM-Y2190 the best producer, its cultures reaching 1.63 ± 0.09 g/L after 55 hr, showing a productivity of 29.59 ± 1.55 mg/(LÁhr), as glucose affected the metabolites pool and redirected yeast metabolism. R mucilaginosa UFMG-CM-Y3647 was selected for scaled-up cultivations in a 2-L bioreactor, where pH-controlled pH 5.5 and aeration of 2.5 vvm was found to be the best condition to improve VA productivity, attaining final concentrations of 1.20 ± 0.02 g/L −1 (78% molar yield) and a productivity of 40.82 ± 0.57 mg/(LÁhr).

Low-Temperature Biodegradation of Lignin-Derived Aromatic Model Monomers by the Cold-Adapted Yeast Rhodosporidiobolus colostri Isolated from Alpine Forest Soil

“…A number of yeasts, some of them isolated from soil, have been described to utilize a range of lignin-derived aromatic monomers, such as FA, HBA, CA, PCA, and VA, as sole carbon and energy sources [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. The biodegradation of mixtures of lignin-derived model compounds, as described in our study, has only been reported for bacteria [ 39 ].…”

“…An important factor in biotechnological applications is temperature. The degradation of lignin-derived aromatic monomers by yeasts has been generally assessed under mesophilic temperature conditions (mostly at 24–30 °C; [ 3 , 9 , 16 , 18 , 19 , 21 , 22 ]). Sampaio [ 17 ] applied temperatures in the range of 17–22 °C.…”

“…The assimilation of intermediates of lignin degradation, such as various low-molecular-weight aromatic compounds (e.g., ferulic acid, 4-hydroxybenzoic acid, p -coumaric acid, vanillic acid, and protocatechuic acid) by basidiomycetous and ascomycetous yeast strains has been reported in a number of studies [ 9 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Basidiomycetous yeasts have a greater capacity to utilize low-molecular-mass lignin-derived aromatic compounds as sole sources of carbon and energy than ascomycetous yeasts [ 9 ].…”

“…The degradation of lignin-derived aromatic compounds by yeasts has been generally assessed under mesophilic temperature conditions (mostly at 24–30 °C; [ 3 , 9 , 16 , 18 , 19 , 21 , 22 ]); Sampaio [ 17 ] applied temperatures in the range of 17–22 °C. In contrast to the recently shown bacterial utilization of lignin and linin-related compounds at low and moderate temperatures [ 11 , 23 , 24 ], knowledge on the role of degradation capacities of yeasts in these temperature regimes is still scarce.…”

Production of Some Higher Alcohols and Acetate Esters from Rice Bran by Yeasts Metabolisms of Kluyveromyces Marxianus and Debaryomyces Hansenii

“…Microbial fermentation has been gaining avor scientists and manufacturers attention for decades because of avor compounds produced enzymatic and microbiological processes are de ned as "natural avors" (European Council Directive, Directive 88/388/88 EEC). The growing of perception and desire for natural products by consumer also drawn on the development biotechnological process for the natural bio-products [4]. Today, agricultural wastes or by-products are emphasized as favorable sources in terms of economic and environmental impact to obtain a high added value product by microbial fermentation.…”