[Biopython] Memory use - alignment formats

[Tanya Golubchik]

Hello,

I'm looking for the most memory-efficient way to write a large number of 
very long sequences (several Mb each) to a file. This works easily with 
a generator passed to SeqIO.write if I'm writing in a sequential format 
like multifasta, but what about, say, phylip?

It is better/equivalent to convert the alignment to a list first 
(obviously using a lot of memory in the process), or to write to a 
multifasta file, then use SeqIO.convert?

Thanks,
Tanya