Here is a link to a description of this yarn at yarndex.com [
www.yarndex.com]
You could substitute another DK weight yarn -- cotton, linen, cotton/acrylic -- that would provide a similar amount of yardage for the 50 gm put-up. DK weight is slightly finer than worsted weight and a little thicker than sport weight.
Cotton can be processed in different ways so that it can have a bit of shine to it, be very matte in finish, be harder to the hand -- more like string in texture -- or soft with a loose twist. Depending upon what yarn you ultimately get, you may achieve gauge and overall size but the appearance may be different depending upon the finish of your yarn. This isn't a bad thing, just something to be aware of.