This a quote from some guy on the babblebelt on making a Berliner Weisse more sour:
"Vinnie from Russian River has given me the tip to make a starter for Lacto and Pedio with 80% malt and 20% apple juice
Pedio apparently produces lactic acid and does not produce alcohol. It also seems to be a better/bigger producer of lactic acid then Lactobacillus. I think for my next 'to style' Berliner Weisse I may try using both Lacto and Pedio.