This review aims at providing an overview on the microbial production of vanillin, a new alternative method for the production of this important flavor of the food industry, which has the potential to become economically competitive in the next future. After a brief description of the applications of vanillin in different industrial sectors and of its physicochemical properties, we described the traditional ways of providing vanillin, specifically extraction and chemical synthesis (mainly oxidation) and compared them with the new biotechnological options, i.e., biotransformations of caffeic acid, veratraldehyde and mainly ferulic acid. In the second part of the review, emphasis has been addressed to the factors most influencing the bioproduction of vanillin, specifically the age of inoculum, pH, temperature, type of co-substrate, as well as the inhibitory effects exerted either by excess substrate or product. The final part of the work summarized the downstream processes and the related unit operations involved in the recovery of vanillin from the bioconversion medium.
The synergic effect of eight salts on D-xylose to xylitol bioconversion by Debaryomyces hansenii NRRL Y-7426 was optimized through a central composite design (CCD) in shaker flasks. Optima conditions were then assayed using detoxified corncob hemicellulosic hydrolyzates as the carbon source, increasing the fermentative parameters to Q P = 0.118 g/L•h and Y P/S = 0.45 g/g from Q P = 0.101 g/L•h and Y P/S = 0.39 g/g (without supplementation). Finally, the process was successfully scaled up to a 50 L Braun Biostat D50 fermenter, since the time of fermentation was reduced from 103 h to 42.8 h and the fermentation parameters increased to Q P = 0.395 g/L•h and Y P/S = 0.59 g/g using a synthetic medium and Q P = 0.236 g/L•h and Y P/S = 0.39 g/g with detoxified hydrolyzates. All the results confirmed the positive influence of supplementing synthetic culture media or detoxified corncob hydrolyzates with salts for the development of D. hansenii.
The efficiency of microbial transglutaminase (MTG) obtained from Streptoverticillum ladakanaum fermentation of sorghum grain and DDGS hydrolysates (HMTG) in increasing the mechanical properties of restructured meat and fish products was evaluated in this study. Gels were obtained by adding HMTG or commercial MTG at 0.3 U/g, and controls lacked enzyme. All treatments were supplemented with 2.0% NaCl. The gels with enzyme showed a lower amount of expressible water, similar to those obtained with CMTG (6% for fish gels and 8% for beef gels). Texture values were also similar. The results showed the feasibility of employing MTG obtained from sorghum hydrolysates.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.