Cryopreservation of microalgae from desert environments of Qatar

Abstract

The Qatar University Culture Collection of Cyanobacteria and Microalgae (QUCCCM) is a unique resource containing a diverse collection of microalgae and cyanobacteria, isolated from the Qatar desert environment. In order to ensure maximum preservation of this resource, a number of cryopreservation techniques were applied to various strains, and the preservation effectiveness (cell viability and lipid productivity) was determined. The conditions tested were direct, passive, and freeze-cooling cryopreservation (technique), dimethyl sulfate and methanol (cryoprotectant), and 5 and 10 % cryoprotectant concentrations over storage durations of up to 1 year. It was shown that the cryopreservation regime is strain dependent, and strains belonging to the same genera can have different requirements. On the other hand, neutral lipid estimation, via Nile red fluorescence determination of pre-and post-cryopreserved microalgae isolates, confirmed that the lipid production is affected by the applied cryopreservation method.

Short-term deleterious effects of standard isolation and cultivation methods on new tropical freshwater microalgae strains

“…3B ). Saadaoui et al (2016) confirmed that the lipid production could be affected by the cryopreservation method that could result in an increase and decrease in lipid content. When the two cryopreservants were compared, a higher lipid content was observed in the biomass that was cryopreserved with glycerol.…”

“…3A ). Saadaoui et al (2016) reported that Scenedesmus cells rapidly recover after 1 month of storage in liquid nitrogen using dimethyl sulfate as cryoprotectant. Microalgae exhibited differences in growth rate among different strains (ANOVA, F = 925.02, p < 0.001, d f = 3; post hoc in Table 1 ).…”

Short-term deleterious effects of standard isolation and cultivation methods on new tropical freshwater microalgae strains

“…R3 showed no significant difference in growth rate between before and after of cryopreservation, unlike other 2 strains. Saadaoui et al (2016) reported that Scenedesmus cells are rapidly recovered after 1 month storage in liquid nitrogen using dimethyl sulfate as cryoprotectant.…”

Short-term deleterious effects of standard isolation and cultivation methods on new tropical freshwater microalgae strains

“…However, high temperatures can severely affect the 14 productivity of said systems (Béchet et al, 2013). For this reason, it has become important the 15 isolation and characterization of high temperature-tolerant microalgal species in order to Chlorella and Scenedesmus (Silkina et al, 2017). However, wastewater has an elevated amounts 1 of nitrogen, phosphorus and microbes, which could affect algal productivity (Mara, 2004; 2 Mahapatra & Ramachandra, 2013) Therefore, an efficient strategy to mitigate potential negative 3 effects of the use of wastewater as culture media is the isolation of wild algal strains that 4 proliferate in it (Mahapatra & Ramachandra, 2013).…”