Kudos for riding such distances with your bike to work; you are already benefiting so much from this! This is why you can count each ride and put it into your timesheet. However, assuming that you probably don’t want to show up all sweaty at work, your bike ride to work will – more likely than not – not be as physically intense as an actual workout.
What’s more, the 30-minute workout units should not be split (unless you have a medical reason). Having said this, if you have a long way to work or another destination by bike (min. 30 minutes) and you do end up arriving all sweaty (to the point where you need a shower) – in other words, you have used this opportunity to do some cardio – then you can count it as one of your 30-minute workouts. Just use your judgment.