Biomolecule Algae species studied Observations Conclusions Ref Proteins         Adhesion proteins Coccomyxa sp. and Glaphyrella trebouziodes Amide III band peaks at 1224 cm-1 and 1260 cm-1 Consistent with generic amyloid structure with strong hydrophobic core 55 Hemoglobin C. Eugametos Fe-CN ferric derivative peak at 440cm-1 1502 cm-1 and 1374 cm-1 peaks Fe-C-N moiety adopts highly bent structure due to H bonding Six coordinated low spin heme iron with distal ligant tyrosinate 38 Carbohydrates         Polysaccharides   Peaks in the range 350-600 cm-1 Skeletal pyranose ring modes Glycosidic stretching modes CH2 and C-OH deformations 56,44 β-D-glucosides   377 cm-1 characteristic peak   56,44 α-D-glucosides   Strong peaks from 479 to 483 cm-1 Peak at 543cm-1 Peaks from Amylopectin and amylase Dextran peak 56,44 Alginates   Peaks at <1300 cm-1 Peaks at >1300 cm-1 (Figure 2) Vibration of polymer backbone Stretching vibrations of carboxylate groups 46 Calcium Alginate   Change of band position from alginates Most prominent: 1413 cm-1 to 1433 cm-1 Symmetric COO- stretching peak 46 κ-carrageenan and ι-carrageenan Eucheuma cottonii Eucheuma spinosa Various peaks from 700 to 1200 cm-1 Peaks are assigned to respective molecular structure of carrageenans 48             Lipids         Hydrocarbons (Figure 3) Botryococcus braunii 1650-1670 cm-1 and 2800-3000 cm-1peaks Double bond stretching peak in long chain unsaturated hydrocarbons 57   Chlorella sorokiniana Neochloris oleoabundans 1650 cm-1 peak 2800-3000 cm-1 peak C=C stretching peak C=C-H vibration peak 16   Botryococcus sedeticus Chlamydomonas sp. Trachydiscus minutes 1656 cm-1 peak 1445 cm-1 peak cis C=C stretching mode proportional to no. of unsaturated bonds CH2 scissoring mode proportional to no. of saturated bonds Trachydiscus minutus has significantly higher content of unsaturated fatty acids 56   Pigments: Chlorophylls         Chl a (Figure 4)   Peaks in the range 1100-1600 cm-1 Peaks in the range 700-950 cm-1 Peaks <700 cm-1 and from 900-1000 cm-1 Strong 306 cm-1 peak and absence of 317 cm-1 peak Stretching motions of C-C and C-N bonds Planar deformations of tetrapyrrol macrocycle Mg related vibrations Mg atoms in hexacoordinated state 35 Chl b   Peaks similar to Chl a Chl a and Chl b have very similar structure 35 Chl c (Figure 5)   1361 cm-1 peak C-N ring breathing mode 58 Chl d (Figure 6) Acaryochloris marina Very different Raman response as compared to Chl a and Chl b Presence of formyl group at C-3 position 37     Pigments: Carotenes         β-carotene (Figure 7) Chlorella sorokiniana Neochloris oleoabundans Euglena, Chlamydomonas Peak at 1520 cm-1 Peak at 1157 cm-1 Peak at 1000 cm-1 Strong peak in the eyespot region C=C stretching mode C-C stretching mode C-CH3 stretching mode High content of carotenoids in eyespot region 59, 16, 51-52, 60 Nucleic acids         DNA and RNA   Peaks between 600 cm-1 and 800 cm-1 Intense peak at 1671 cm-1 Peak at 1100 cm-1 Ring breathing modes of DNA and RNA bases C=O stretch vibrations Symmetric PO-2 stretching vibration 53

Table 1: Studies on biomolecules in algae using Raman spectroscopy.