Production of ellagic acid from degradation of valonea tannins by Aspergillus niger and Candida utilis

Abstract

Two fungal strains, effective in converting valonea (Quercus aegilops) tannins into ellagic acid (EA), were isolated from soil contaminated by valonea tannins, and were tentatively identified as Aspergillus niger and Candida utilis. Properties of EA accumulation by the two isolates from valonea tannins' fermentation were studied. Both the strains preferred sucrose to glucose as the additional carbon and energy source. The most suitable concentrations of valonea tannins in fermentation media for EA accumulation by A niger and C utilis were 5.0 and 9.0 g dm −3 with EA yields of 12.1 and 8.9% (w/w), respectively. The optimal temperature for the two strains was 28• C, while the preferred pH values of the fermentation media were 4.5-5.0 for A niger and 4.8-5.2 for C utilis. The tannin tolerances of A niger and C utilis were adapted to 20 and 25 g dm −3 by gradually increasing the concentrations of valonea tannins in the culture media. The adapted strain of A niger was able to completely degrade 20 g dm −3 valonea tannins with an EA yield of 14.3% in 9 days. Meanwhile, the adapted strain of C utilis decreased the valonea tannins' level from 25 to 9.1 g dm −3 with an EA yield of 11.48%. The degradation ability of A niger came from tannase whose activity in the medium was 63 U cm −3 at the ninth day of fermentation, and that of C utilis was due to both tannase and polyphenol oxidase (PPO) whose activities were 32 U cm −3 and 29 U cm −3 at the ninth day. The coculture of both the adapted strains could completely degrade 25 g dmvalonea tannins in only 7 days with a remarkably increased EA yield (21%). The activities of tannase and PPO of the coculture at the seventh day were 66 U cm −3 and 47 U cm −3 respectively, which proved the synergistic effect of the two enzymes on valonea tannins' degradation and EA accumulation.

Ellagic acid production by Aspergillus niger in solid state fermentation of pomegranate residues

“…DiVerences in time of tannin acyl hydrolase production and EA accumulation can be explained by the fact that gallotannins are more biodegradable than ellagitannins as described recently by Mingshu et al [21] and Aguilar et al [3]. The EA production was higher than the values reported by other [14,[27][28][29]; however, the optimization of the process to produce EA is necessary. In addition, EA accumulation was not associated with tannin acyl hydrolase activity and it partially supported the hypothesis proposed by Aguilar et al [3] about the diVerence between the tannin acyl hydrolase (gallo-tannase) and the unknown "ellagi-tannase."…”

“…Recent studies on EA production are very scarce but they are very promising and they have reported the use of cranberry pomace fermented in a solid state culture using Lentinus edodes [28,29]; authors attributed the catalysis to the enzyme -glucosidase, Also, valonea tannins have been used to produce EA in axenic culture of Aspergillus niger SHL [14] or in co-culture of Candida utilis and A. niger [27]. However, low yields and long times are involved in the bioprocess.…”

Combined biodegradation and ozonation for removal of tannins and dyes for the reduction of pollution loads

“…A. niger and Candida utilis isolated from valonea tannin fermentation preferred sucrose to glucose as the additional carbon and energy source. These strains were able to degrade 20 g dm −3 valonea tannins completely with an ellagic yield of 14.3% in 9 days (Shi et al 2005). It has been found that Escherichia coli degrades phenol compound and also helps in simultaneous reduction of Cr(VI) to Cr(III) (Shen et al 1995).…”

Ellagic Acid Production from Biodegradation of Creosote Bush Ellagitannins by Aspergillus niger in Solid State Culture

“…However, about the enzyme(s) involved in the process of ellagitannins biodegradation, the information is scarce and confuse. Shi et al (2005) hypothesized the role of typical tannase (tannin acyl hydrolase, TAH) and polyphenol oxidase in this biochemical event. Some reports of tannin biodegradation have been published (Bath et al 1998;Aguilar et al 2007), and the role of a nontypical tannase (ellagitannase) has been seriously considered and partially demonstrated in the studies carried out by Huang et al (2007a, b, c, d).…”

“…1). To obtain EA from plants, some studies on hydrolyzing ellagitannins with acid or base have been reported (Daniel et al 1991;Shi et al 2005). Due to variation in plant sources, the differences of ellagitannins structure, and the difficulty of purification, these chemical methods often lead to low yields of EA and considerable impurities.…”