Tel Aviv University researchers have successfully produced hydrogen from plants. They injected chlorophyll cells with the enzyme hydrogenase that, with sunshine, produced a tiny but constant supply of hydrogen. This is a breakthrough, as hydrogen produces no pollutants when used as a fuel.
https://www.calcalistech.com/ctech/articles/0,7340,L-3831651,00.html
https://pubs.rsc.org/en/content/articlelanding/2020/ee/c9ee03859k#!divAbstract