The hydrogen production of photosynthetic bacteria (PSB) in a micro-channel photobioreactor was experimentally investigated and the interaction between PSB and gas-liquid interface was observed.It was found that the bubble originated at the rough sidewall surface of the microchannel and grew as a result of the gas molecules transfer across the gas-liquid interface.The bubble growth rate was accelerated by increasing liquid flow rate.It was also observed that a bubble gradually shrank down to dissolve in the liquid phase.Meanwhile

the irreversible adsorption of PSB onto the gas-liquid interface and the mutual repulsion between PSB and gas-liquid interface were revealed.The absorbed PSB did not stick on the bubble surface but slipped around the interface.Furthermore

the absorbed PSB on the gas-liquid interface enhanced the mechanical strength and stability of the bubbles

hence resulting in an impediment to the coalescence of bubbles.