High-throughput and real-time microalgae monitoring platform using lens-free shadow imaging system (LSIS)

Floc size analysis is one of the major processes in bio-flocculant efficiency determination, which is critical for microalgae harvesting. Till now the flocculation analysis has been performed by using photospectrometry. In this conventional method, optical density of a sample is measured in a time interval by collecting the sample from a fixed point of the container, up to ~5 hrs of observation period. This time consuming process may not guarantee the viability of the algae, which limits the efficient harvesting. To address this issue, we introduce a real time flocculation monitoring system based on the lens-free shadow imaging technique (LSIT). This simple, fast, and cost-effective system automatically analyzes the thousands of single microalgae all in parallel and monitors their flocculation by using a custom developed algorithm. We evaluate the performance of this approach by comparing the results with the standard method, showing a good agreement between two modalities.