Rapid Characterization of Microalgae and Microalgae Mixtures Using Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS)

Abstract

Current molecular methods to characterize microalgae are time-intensive and expensive. Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) may represent a rapid and economical alternative approach. The objectives of this study were to determine whether MALDI-TOF MS can be used to: 1) differentiate microalgae at the species and strain levels and 2) characterize simple microalgal mixtures. A common protein extraction sample preparation method was used to facilitate rapid mass spectrometry-based analysis of 31 microalgae. Each yielded spectra containing between 6 and 56 peaks in the m/z 2,000 to 20,000 range. The taxonomic resolution of this approach appeared higher than that of 18S rDNA sequence analysis. For example, two strains of Scenedesmus acutus differed only by two 18S rDNA nucleotides, but yielded distinct MALDI-TOF mass spectra. Mixtures of two and three microalgae yielded relatively complex spectra that contained peaks associated with members of each mixture. Interestingly, though, mixture-specific peaks were observed at m/z 11,048 and 11,230. Our results suggest that MALDI-TOF MS affords rapid characterization of individual microalgae and simple microalgal mixtures.

Characterization of microbial mixtures by mass spectrometry

“…Model mixtures of microalgae produced spectra with peaks not found in the spectra of individual microalgae composing the mixture—Fig. . The biochemical origin of these mixture‐specific peaks is unclear, and their possible utility in mixture characterization warrants further investigation.…”

“…MALDI mass spectra of monoalgal cultures of (A) Chlorella vulgaris UTEX 395, (B) Scenedesmus acutus LRB‐AP 401, and (C) Chlorella sorokiniana UTEX 1230 lack biomarkers, for example, at m/z 11 048 and m/z 11 230, observed in (D) a binary mixture of Chlorella vulgaris UTEX 395 and Scenedesmus acutus LRB‐AP 401 and (E) a tertiary mixture of all three microalgae. Reprinted with permission from Barbano et al…”

MALDI-TOF mass spectroscopy of yeasts and filamentous fungi for research and diagnostics in the agricultural value chain

“…However, the identification of microorganisms from mixed or complex samples derived, for example, from patients, the environment, or infected plant tissue or food by MALDI-TOF MS is an important goal. So far, only a few reports have demonstrated the identification of bacteria and microalgae in mixtures by using biomarkers or correlation coefficients [83][84][85]. These studies have shown that ion suppression can affect the detection of specific masses of one or the other microorganism and thus complicate species identification in mixed samples [83,84,86].…”

“…So far, only a few reports have demonstrated the identification of bacteria and microalgae in mixtures by using biomarkers or correlation coefficients [83][84][85]. These studies have shown that ion suppression can affect the detection of specific masses of one or the other microorganism and thus complicate species identification in mixed samples [83,84,86]. On the other hand, novel mass peaks only observed in the mixed sample were discovered and may serve as biomarkers for mixtures or contaminations [83,86].…”

“…These studies have shown that ion suppression can affect the detection of specific masses of one or the other microorganism and thus complicate species identification in mixed samples [83,84,86]. On the other hand, novel mass peaks only observed in the mixed sample were discovered and may serve as biomarkers for mixtures or contaminations [83,86]. For samples that contain more than two organisms, species identification based on biomarkers that invariably indicate the presence of a particular species performed better than correlation-based methods [84].…”