A rapid and reliable method for estimating microalgal biomass using a moisture analyser

• Published in: Journal of applied phycology 2016-06, Vol.28 (3), p.1725-1734
• Main Authors: Ratha, Sachitra Kumar, Rao, Polur Hanumantha, Govindaswamy, Kanchan, Jaswin, Rajeshkumar Sam, Lakshmidevi, Rajendran, Bhaskar, Sailendra, Chinnasamy, Senthil
• Format: Article
• Language: English
• Subjects: Algal growth; Arthrospira; Biofuels; Biomass; Biomedical and Life Sciences; Botryococcus braunii; Cell morphology; Chaetoceros; Chlamydomonas; Chlorella; Drying; Ecology; Freshwater & Marine Ecology; Life Sciences; Microalgae; Plant Physiology; Plant Sciences; Power consumption
• ISSN: 0921-8971; 1573-5176
• DOI: 10.1007/s10811-015-0731-1

A rapid and efficient estimation of microalgal biomass is very important to assess the growth performance of algal strains used for the production of biofuels and other high-value products. Areal and volumetric productivities of biomass are considered important in algal growth studies. A fast and reliable method for the measurement of microalgal biomass using a moisture analyser was standardised and validated in this study using different microalgal strains, viz., Botryococcus braunii , Chlamydomonas sp., Chlorella sp., Arthrospira sp. and Chaetoceros sp. Conventional oven-drying method was compared with moisture analyser method for analysis time, accuracy and repeatability. The average time required for analysis using a moisture analyser was 22:0, 12:38, 9:03 and 7:08 (min:s), respectively, at 60, 80, 100 and 120 °C for B. braunii . For the algal cultures with 0.1–1.2 g L −1 cell concentration, 10-mL culture volume was sufficient to get reliable dry weight using moisture analyser. To measure large number of samples, a modified method was developed which required pre-drying of samples in hot air oven at 80 °C for 15 min prior to dry weight measurement in a moisture analyser at 100 °C. The drying time in the moisture analyser varied based on the cell morphology. Unicellular Chlorella sp. with highest cell concentration of 1.2 g L −1 required less than 10 min of drying time, whereas the filamentous Arthrospira sp. with cell concentration of 1.1 g L −1 required about 15 min. Time required for the dry weight analysis of 100 samples using modified moisture analyser method was 281:40 (min:s), and the total power consumption was 2.45 kWh, which was significantly lower than the analysis done using conventional oven-drying method.