Vivi Joosten

Expression and production of llama variable heavy-chain antibody fragments (VHHs) by Aspergillus awamori

We report the expression and production of llama variable heavy-chain antibody fragments (VHHs) by Aspergillus awamori. Fragments encoding VHHs were cloned in a suitable Aspergillus expression vector and transformants secreting VHH fragments were analysed for integrated gene copy-numbers, mRNA levels and protein production. Functional VHHs were detected in the culture medium, indicating the feasibility of producing this type of protein in a fungal expression system. Secreted VHHs were subjected to (extracellular) degradation, which could be partially prevented by the addition of BSA to the culture medium.

Efficient production of Arthromyces ramosus peroxidase by Aspergillus awamori

The heterologous production of Arthromyces ramosus peroxidase (ARP) was analysed in the filamentous fungus Aspergillus awamori under control of the inducible endoxylanase promoter. Secretion of active ARP was achieved up to 800 mg l(-1) in shake flask cultures. Western blot analysis showed that an rARP product of the correct molecular weight was produced. In contrast to several other studies about heterologous production of heme containing peroxidases, our results suggest that in A. awamori no heme limitation exists during overproduction of ARP.