Lactaid brand lactase enzymne is harvested from fungi, according to the
manufacturer (several years ago).  They recommended nursing moms put a drop on
their nipple before latching baby on.  I would first try improving management
to  get more fat into the milk and therefore into the baby (freq feeds with
better milk removal, one breast per feed if neccessary).
Catherine Watson Genna, IBCLC  NYC  [log in to unmask]