A novel method has been developed to estimate the biomass and pigment concentration of algae, without ever having to touch or disturb the organism.

Dennis C. J. Kharagpur writes in Research Matters that scientists from Indian Institute of Khragpur (IIT KGP) have developed a novel method to estimate the biomass and pigment concentration of algae, without having to touch or disturb the organism. The new process could help industries, such as the pharmaceutical and food industries, with quick tests of their yield.

Two important factors that are required to deduce the yield of fuels or other usable products from a colony of algae are biomass and the pigment concentration of the colony. This often involves intrusive or destructive testing methods, which require collecting samples from the colony. To avoid such intrusive measures, scientists from IIT KGP have developed an optical-based testing method to determine the two properties.

The technique, called diffuse reflectance spectroscopy (DRS), involves analyzing the infra-red and visible radiation scattered from a sample using a spectrometer.

For their experiment, the scientists used two species of algae; Chlorella Vulgaris and Nostoc muscorum, and a mixed culture of the two species. Visible to near infra-red (VisNIR) light was scattered off of samples of the two cultures, and then sent through a spectrometer, which split the emerging light into its constituent frequencies. Next, using a partial least squares regression (PLSR) algorithm, the spectrum was analyzed to reveal the biomass and pigment concentration of the cultures.

The analysis of the spectra also revealed culture-specific spectral signatures, allowing the scientists to identify the specific culture based on the spectra it produced. The amount of carotenoids, a type of organic pigment present in all photosynthetic organisms, like plants and algae, was also deduced using the PLSR method on the spectra.

This new method of testing for pigments, according to the scientists, has the potential for developing a new approach for estimating pigment concentrations in algae samples without consuming the sample. And if commercialized, could reduce the time and effort required to convert algae into a viable industry resource.

Read More