Bioengineering yeast to enhance folate levels in wine

Enhancing the natural folate level in wine using bioengineering and stabilization strategies

“…The total folate content in the wine was determined using microbiological assay with chloramphenicol-resistant Lactobacillus casei as the test microorganism (Shrestha, Arcot, & Paterson, 2000;Walkey et al, 2015). Wine samples were incubated with chicken pancreas conjugase solution at 37°C for 3 h and heated at 100°C for 5 min to denature the enzyme.…”

“…Overexpression strains for ABZ2, DFR1, FOL1, FOL3 and MIS1 in Saccharomyces cerevisiae were constructed as described previously (Walkey et al, 2015). Briefly, an overexpression DNA cassette was generated by PCR for each gene, using the pCW1 vector (Walkey et al, 2012).…”

“…The sequences of oligonucleotide primers used are listed in Supplementary Table 1. The construction of the FOL2, ABZ1, and FOL2/ABZ1 overexpression strains was described previously (Walkey et al, 2015).…”

“…Small-volume wine fermentations were performed with sterile-filtered Chardonnay and Pinot Noir grape juice, as described (Walkey et al, 2015). The relevant yeast strains were grown to log phase in standard lab media, then used to inoculate 70 ml of juice at a cell density of 0.2 OD 600 /ml.…”

“…Bioengineering of yeast has proven to be an important tool for developing new alcoholic beverages with important value-added qualities (Husnik et al, 2006;Pires, Teixeira, & Vicente, 2014;Walkey, Luo, Madilao, & van Vuuren, 2012). In a recent study, we enhanced the folate level in wine by overexpressing a wine yeast gene that is involved in folate biosynthesis (Walkey, Kitts, Liu, & van Vuuren, 2015). However, regardless of these advances in folate biofortification, the stability of natural folate in food systems remains a limiting factor, if concentrations are not able to be sustained over extended time periods (Gujska & Majewska, 2005;Gujska, Michalak, & Klepacka, 2009;Indrawati Arroqui, Messagie, Nguyen, Van Loey, & Hendrickx, 2004;Liu et al, 2012;Ohrvik & Witthoft, 2008 goal to further enhance the natural folate in wine, and also to develop a strategy whereby the increased natural folate in the wine product would be stable after opening and storage.…”