You can use the regex package and the .findall() method:
In [1]: s = "11101110001011101000000011101010111"
In [2]: import regex
In [3]: regex.findall(r"(?<=000|^)\d+?(?=000|$)", s)
Out[3]: ['1110111', '1011101', '0', '00011101010111']
The 000|^ and 000|$ would help to match either the 000 or the beginning and the end of a string respectively. Also note the ? after the \d+ - we are making it non-greedy.
Note that the regular re.findall() would fail with the following error in this case:
error: look-behind requires fixed-width pattern
This is because re does not support variable-length lookarounds but regex does.