The pH Tolerance of Chlamydomonas applanata (Volvocales, Chlorophyta)

Abstract

The effects of hydrogen ions on the growth and ultrastructure of Chlamydomonas applanata Pringsheim were examined. This species exhibits wide tolerance growing at pH values ranging from 3.4 to 8.4, with optimum growth obtained at 7.4. Growth is noticeably depressed at pH 4.4 and 3.4. At the ultrastructural level, exposure to pH 4.4 results in a 10% decrease in cell volume of single vegetative cells, an increase in pyrenoidal volume, and reduction of starch reserves. Palmelloid colonies also appear. pH 3.4 induces excessive production of mucilage and leads to the preponderance of palmelloid colonies. Cell death of both colony and single cells is seen, as well as loss of motility and abnormal cell division. Surviving single cells are significantly larger than controls, with thicker cell walls, smaller chloroplasts, and larger vacuome. Such cells entering dormancy ensure the survival of the species in times of stress.

Effects of Environmental Factors and Nutrient Availability on the Biochemical Composition of Algae for Biofuels Production: A Review

“…As previously stated, most species of algae grow maximally around neutral pH (7.0-7.6). This has been observed in studies of Ceratium lineatum, Heterocapsa triquetra and Prorocentrum minimum [118] and Chlamydomonas applanata [31]. Visviki and Santikul [31] studied the growth of Chlamydomonas applanata within a pH range 1.4 to 8.4 with 1 point increments.…”

“…This has been observed in studies of Ceratium lineatum, Heterocapsa triquetra and Prorocentrum minimum [118] and Chlamydomonas applanata [31]. Visviki and Santikul [31] studied the growth of Chlamydomonas applanata within a pH range 1.4 to 8.4 with 1 point increments. No growth was observed from pH 1.4 to 3.4, above which tolerance of pH in C. applanata was observed (with optimum growth observed at 7.4).…”

“…Environmental factors such as temperature, light, pH, and nutrients not only affect photosynthesis and growth rate of the algae, but also influence the activity of cellular metabolism and composition. These effects have been identified individually by researchers [25][26][27][28][29][30][31], however, no consolidated review on the effect of these factors on algae is available. Most of the recent reviews have focused on production and processing techniques [11,16,32] with few data on the impacts of environmental and nutritional factors on algal growth rates.…”

Distribution and seasonal variability in the benthic eukaryotic community of Río Tinto (SW, Spain), an acidic, high metal extreme environment

“…Members of the Chlorophyta such as Chlamydomonas, Dunaliella, Chlorella, and Euglena, were the most frequent species, forming large green patches along the river bed. These species are known for their high metal and acid tolerance [15,44] and show the same patchy distribution found in other acidic environments [20]. The most acidic sampling station of the river, RI, is inhabited by an eukaryotic community dominated by two species related to Dunaliella and Cyanidium.…”

Potential for green microalgae to produce hydrogen, pharmaceuticals and other high value products in a combined process

“…Low external pH is, like some other forms of stress, shown to induce production of heat shock proteins (Gerloff-Elias et al , 2006). Effects of exposure to pH stress in Chlamydomonas applanata include reduction of cell volume, increase in pyrenoidal volume, reduction of starch reserves, and production of mucilage leading to palmelloid colonies (Visviki and Santikul, 2000). Haematococcus has shown increased astaxanthin production at low pH when exposed to light stress and N-deprivation (Orosa et al , 2001).…”