Improving hydrogen production of Chlamydomonas reinhardtii by reducing chlorophyll content via atmospheric and room temperature plasma

Reduction of chlorophyll size has great advantages on improving the photosynthesis efficiency as well as the photolysis algal H-2 production. To promote the H-2 production, Chlamydomonas reinhardtii was mutated by atmospheric and room temperature plasma (ARTP). After the selection, an algal mutant was observed to have 1.8-5.2 times (28.5-84.1 mL L-1) and 2.7-3.1 times (356.5-405.2 mL L-1) higher H-2 production than wild-type during the algal subcultures grown in pure and co-cultures, respectively. In comparison with wild-type alga, the mutant grew as lighter green colonies on agar plate, with about 2 times larger cell diameter and 5.3-6.1 times lower chlorophyll content per unit cell volume. Results from the comparative transcriptomic analysis indicated that most of the genes relating to photosynthesis (photosystem I, II, cytochrome b6/f complex, photosynthetic electron transport, and F-type ATPase) and LHC proteins were have higher expressions in mutant cells, suggesting the improvement of photosynthesis efficiency.