Photobioreactros are key apparatus in microagal cutlure, and play an important role in exploitation of microalgae bioresources (e.g. microalgal feedstocks, biodiesel and bioactive compounds). Due to the dual restriction of technique and transparent materials, current photobioreactors both domestic and international are generally limited to a relative small-scale, which are only fit for basic research in the laboratory. Large-scale photobioreactors suitable for carrying out pilot scale cultivation and industrial production are rare. The magnification of photobioreactors to industrial scale is one of the confinement factors that restrict the exploitation of microalgal resources.

A team of specialists organized by Planning Financial Bureau of Chinese Academics of Sciences took an acceptance test on the project of Large-scale closed parallel tubular photobioreactor for algal cells cultivation engineering, which was directed by the Phycological Biotechnology Group in Institute of Oceanology, Chinese Academy of Sciences. A report about the schedule, financial and testing was given by Prof. Jianguo Liu. The experts looked over the operating state of the photobioreactor in situ, checked the performance index of equipments and examined on relevant files and financial account. After discussion, the experts highly appreciated the effective organization, research progress and innovativeness of the project. The conclusions they reached on this project were as follows:

1. Establishment of two parallel tubular photobioreactors applied to pilot scale cultivation and industrial production with capacity of five tons and specific surface area at 0.74 has been accomplished by this project, which would provide an ideal solution to the technical difficulty of specific surface area decreasing substantially with the increase of photobioreactor volume. The equipment can clean the adherent cells automatically lessening the dead angles.

2. Velocity of the liquid was uniform and controllable during operation, and violent turbulence was formed in the fluid. Automatic data collection and programme control was implemented by employing related sensors and modules, which can effectively control the main cultivation parameters (e.g. temperature, pH, dissovled oxygen etc.). Problems of oxygen resolving and CO2 compensation could be solved by this device. So it was well suited for process analysis and optimization of cells cultivation.

3. Main equipment and other relevant components were all ready for operation. During the process, the whole device was working properly and stably, which achieved the preplanned functions and technical indicators. Self-cleaning technology, an attractive lightspot of this project, was a fabulous unique design with practical function. Large-scale cultivation of Haematococcus pluvialis in this apparatus promoted cell density substantially and shortened the culture cycles for 1/4.

The committee agreed that this project had accomplished the objectives in the assignment, and funds expenditure was used properly on schedule. The project obtained unanimous approval. Experts hoped that the research group should keep working on basic and industrial researches about photobioreactors aiming at popularization and application of large-scale photobioreactors in domestic novel microalgae breeding industry, and also promoting exploitation of microalgae resources.

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