Characterization of a novel thermophilic cyanobacterial strain from Taian hot springs in Taiwan for high CO_2 mitigation and C-phycocyanin extraction

摘要

The photosynthetic thermophiles have advantage in sequestering CO_2 emitted from the energy sector due to their adaptation to high temperatures, growth at high concentrations of CO_2, and economically important metabolites. The characterization of such a microorganism, a cyanobacterium from Taian hot springs in Taiwan is described here. This thermophilic cyanobacterium is rod-shaped with a size of 1.2-2.5μm × 6.0-9.0μm. A comparison of the 16S RNA and cpcBA-IGS sequences revealed that it is closely related to Thermosynechococcus elongatus BP-1 and so named as Thermosynechococcus elongatus TA-1. This cyanobacterium has better growth at 10% and 20% CO_2, at 50 C with 6000 lx light intensity, at a starting pH of 7-9 and in a medium with 20 mM NaCl. The preferred nitrogen source is NaNC_3 of which the minimal requirement is 10mM. The purified phycocyanin (C-PC) from TA-1 is still kept native and active at a wide range of temperatures (4-60 C) with a 65.65% activity even at 60 C, as well as pH values from 4 to 9 and thus exhibiting a good thermal and acid-base stability. This thermophilic cyanobac-terium could make integration of CO_2 mitigation from industrial flue gas and production of economically important product, like C-PC, more feasible.