Characterization of Bacillus megaterium, Bacillus pumilus, and Paenibacillus polymyxa isolated from a Pinot noir wine from Western Washington State.

This report provides the first confirmed evidence of Bacillus-like bacteria present in a wine from Washington State. These bacteria were isolated from a 2013 Pinot noir wine whose aroma was sensorially described as being 'dirty' or 'pond scum.' Based on physiological traits and genetic sequencing, three bacterial isolates were identified as Bacillus megaterium (strain NHO-1), Bacillus pumilus (strain NHO-2), and Paenibacillus polymyxa (strain NHO-3). These bacteria grew in synthetic media of low pH (pH 3.5) while some survived ethanol concentrations up to 15% v/v. However, none tolerated molecular SO2 concentrations ≥0.4 mg/l. Growth of strains NHO-1 and NHO-3 in a Merlot grape juice resulted in increases of titratable and volatile acidities while decreases in titratable acidity were noted for NHO-2.

Investigations of aroma volatile biosynthesis under anoxic conditions and in different tissues of "Redchief Delicious" apple fruit (Malus domestica Borkh.).

Disks from different tissues were obtained from "Redchief Delicious" apple fruit (Malus domestica Borkh.) and analyzed for the ability to metabolize 1-pentanol as well as synthesize constitutive esters and alcohols under anoxic and aerobic conditions. The skin tissue displayed a greater capacity to synthesize pentanal, pentyl acetate, pentyl propionate, pentyl butyrate, and pentyl hexanoate than the hypanthial and carpellary tissues during incubation with 1-pentanol. With the exception of pentyl acetate and pentyl propionate biosynthesis, the hypanthial tissue synthesized these compounds at a higher rate than the carpellary tissue. Anoxia inhibited both constituent and 1-pentanol-derived ester biosynthesis. While anoxia inhibited ester biosynthesis, ethanol biosynthesis increased at a greater rate in tissue disks held under these conditions. Biosynthesis of 1-butanol, 2-methyl-1-butanol, and 1-hexanol was greater in tissue disks held in air during the first part of the measurement period and dropped off more rapidly than those transpiring in tissue disks held under anoxic conditions. The biosynthetic rates of all esters, both constituent and 1-pentanol-derived, increased as a result of air exposure. While hypoxic or anoxic conditions may promote ethanol synthesis, these conditions also appear to inhibit the formation of the ethanol-derived esters partially responsible for the off-flavor in apples attributed to ultralow O(2) controlled atmosphere storage.