Alternative algal harvesting technique with the use of the hard clam Mercenaria mercenaria

Algal harvesting is one of the costliest portions of algal biofuels production and finding an alternative is critical to bringing this type of biofuel to the market. This research tested the viability of using the hard clam Mercenaria mercenaria as an alternative algal harvesting technique which converts the algal cells to a partially digested excrement called biodeposits. It was found that increasing the clam density increased the biodeposit rate. Algal density had an impact on the biodeposit rate, but no maximum was found. The presence of ammonia increased the biodeposit production rate within the four hour test period. The mineral composition shows the clams sequester metals, CNHS does not differ from the original algae, ash content and lipid content increased 59% and 63%, respectively, in biodeposits relative to original algae. This is needed in assessing the potential in using biodeposits as a feedstock for further downstream processes.