Realising the biotechnological potential of fungi requires full appreciation of the molecular biology and genetics of this kingdom. We review recent advances in our understanding of fungal genetic structure as it might influence biotechnology; including introns, alternative splicing of primary transcripts, transposons (transposable elements, or TEs), heterokaryosis, ploidy and genomic variation, sequencing, annotation and comparison of fungal genomes, and gene editing. We end by indicating under-researched, but unique, aspects of fungal cell biology that offer opportunities for developing new strategies to manage the activities of fungi to our benefit. As a closing example, we discuss the potential of bioengineering fungi specifically for bioremediation of plastic wastes.