A novel, low cost, sterilizable and disposable in-house culture vessel for laboratory study of microalgae cultures

摘要

Algal industry is expanding as a source of energy, food, feed, recombinant proteins and high value chemicals. As the research need is increasing, many laboratories are getting involved. Photobioreactors are used to achieve uniform light illumination and CO2 supply to achieve faster algal growth. Use of commercially available PBR in algal study is limited to few highly funded laboratories due to large initial capital requirement and high operational cost. To address the issue of uniform light illumination and CO2 supply at low cost, an In-house Culture Vessel (ICV) has been designed and the algal growth was compared between ICV vs. conventional 20L carboys which are generally used in lab for relatively larger quantity of inoculum development. An in-built air-sparger has been provided to achieve both air lift mixing of culture and CO2 supply. The well mixed culture with high surface area allows uniform light illumination. Picochlorum sp. was grown in the designed culture vessel and in conventional carboys. Growth rate in ICV was 16 times more as compared to carboy. This enhanced growth rate indicates more and/or even availability of light to algal cells in ICV compared to carboy as the starting nutrient level was same in both. Growth rate of 0.16 OD/day even at 35 OD in ICV indicates that the culture of Picochlorum sp is still in growing phase in ICV whereas the same culture reached stationary phase in the 20L carboy at 3.73 OD with negligible growth rate of 0.02 OD/day. The proven fact of chlorophyll a/b ratio adjustment in response to light was observed as well with maintained Nitrogen level for Picochlorum sp. The In-House Culture Vessel was demonstrated to be a promising and inexpensive tool which could be used as a closed system for developing actively growing high density microalgae cultures at laboratory scale for further studies.