Letter from N G Heatley to Newforge Ltd, Belfast Have not been concerned with the pectinase of mould cultures - most penicillin is made from Penicillium notatum - special high yielding strains have been selected, but cannot pass these on to people not working on penicillin - discusses effects of certain elements in the medium - does not know how rapidly pectinase destroyed after acidification of the medium - probably the pH could quickly be brought back to a safe level - large amounts of penicillin grown by certain commercial firms - pectinase might be extracted from the rejected mycelial mats or from the spent crude culture medium - believes that one of the large cyder firms and General Foods Inc have done research on pectin and pectinase. 8 September 1944