Nanotechnological approaches to disrupt the rigid cell walled microalgae grown in wastewater for value-added biocompounds: commercial applications, challenges, and breakthrough

Cell disruption is very important for the value-added biocompounds (VAB) to come out from microalgae. Among the most demanding microalgae at industrial level, diatoms and Haematococcus pluvialis have hooked the race. However, they at the same time face difficulty in their cell wall disruption for the VAB to come out as it is very rigid and thick. This is among the major barrier in construction of diatom solar panels for biofuel production. Different diatom walls experience different shear forces for harvesting its biomass. This results in raising the overall cost of photobioreactors controlling their growth and recovery of biomass and VAB. In order to lower the cost, the cell wall of microalgae needs to milk the metabolites without itself getting sacrificed. The current review in depth discusses the techniques to break the cell wall of microalgae especially diatoms and Haematococcus using nanotechnological approaches without lysing the cell. The research gaps, commercial applications, and future research directions have been identified and discussed to strengthen the environmental and economical sustainability.