Conversion from 2-column PDF to "single column" output text

Are there an option to set when calling "pdf2txt" in command line mode, so articles with 2 columns are converted into one consecutive column text file?

[kwalcock]

There is no option. The various PDF converters are themselves responsible for figuring out how many columns the text there are and combining them into a single column. They are similarly responsible for combining lines and pages. Do you know of a converter that can accept a hint about the number of columns?