Function to convert a Python datetime to a Matlab datenum. From http://stackoverflow.com/questions/8776414/python-datetime-to-matlab-datenum/9260102#9260102

datetime2matlabdn.py

from datetime import datetime, timedelta

def datetime2matlabdn(dt):
    ord = dt.toordinal()
    mdn = dt + timedelta(days = 366)
    frac = (dt-datetime(dt.year,dt.month,dt.day,0,0,0)).seconds / (24.0 * 60.0 * 60.0)
    return mdn.toordinal() + frac

just add the following line dt = dt.replace(tzinfo=None)

def datetime2matlabdn(dt):
    dt = dt.replace(tzinfo=None)
    ord = dt.toordinal()
    mdn = dt + timedelta(days = 366)
    frac = (dt-datetime(dt.year,dt.month,dt.day,dt.second)).seconds / (24.0 * 60.0 * 60.0)
    return mdn.toordinal() + frac

this function doesn't really give the same results as Matlab
ex:

s = '2016-01-17T23:00:00.1173350Z'
matlab_datenum = 73635.0
python_datenum = 736346.9583333334

there's a difference by 4 values