Optimization of bead milling parameters for the cell disruption of microalgae: Process modeling and application to Porphyridium cruentum and Nannochloropsis oculata

Microalgal biomass pretreatment for bioethanol production: a review

“…In the field of biotechnology, these technologies have already been used for cellular disruption of some microorganisms and are affected by different parameters such as feed rate of the cell suspension, agitation speed, agitator design, diameter and size of the balls, as well as design of the grinding chamber. Besides biomass concentration, density of the suspension, and microorganism morphology, it is also necessary to take into account the interactions of the equipment with the biomass derived from different microorganisms (Montalescot et al, 2015;Postma et al, 2015). Overall, in spite of the effectiveness of these pretreatments for cellular disruption of microalgae biomass, their main drawback is that they do not directly affect the structure of the intracellular carbohydrates, and therefore, a further step would be needed to modify the starch structure.…”

Screening of freshwater and seawater microalgae strains in fully controlled photobioreactors for biodiesel production

“…Consequently, the cell fragility or the mechanical resistance of the strain is an important criterion for the selection of promising strains for biodiesel production. Recently, Montalescot et al, (2015) investigated cell disruption efficacy of Nannochloropsis oculata and Porphyridium cruentum using high pressure bead milling in the range between 600 and 2700 bar. They found that cell disruption was at its maximum when the pressure applied was between 1500 and 2000 bar.…”

“…For each strain, 40 ml of culture suspension was collected and passed through the disrupter in 4 cycles at a pressure of 1750 bar. Note that this pressure was chosen as the mean value of the optimal disruption pressure range 1500-2000 bars reported for N. oculata cells as previously mentioned(Montalescot et al, 2015). Note that the cell suspension was well mixed in the supply tank before disruption to insure a good homogeneity of the sample.For each strain, cell concentrations N (in cells/ml) was determined under an optical microscope using Malassez counting-chamber before and after the culture grinding, and the percentage of disrupted cells was obtained by ‫݊݅ݐݑݎݏ݅݀‬ Strains cultivation in efficient overproducing screening systemphotobioreactors (EOSS-PBR) and shake flasksAt the pre-screening step all the investigated strains were grown under optimal growth conditions in EOSS-PBR operating in semi-continuous mode with a dilution rate D = 0.24 day -1 (0.01 h -1 ).…”

“…A more detailed description of the disrupter is available in Jubeau et al,(2013) andMontalescot et al, (2015). For each strain, 40 ml of culture suspension was collected and passed through the disrupter in 4 cycles at a pressure of 1750 bar.…”

Extraction of astaxanthin from microalgae: process design and economic feasibility study

“…This interaction is difficult to predict and vary in function of microorganisms, medium viscosity and flow rate. The main operating parameters are the bead filling, bead density, bead diameter, the speed of the agitation and the feed rate [16]. Taking into consideration the high viscosity of the slurry entering the bead miller, ceramic beads specifically alumina (ρ = 3,8 kg/m 3 ) were used in this study [17].…”