Preliminary assessment of terrestrial microalgae isolated from lichens as testing species for environmental monitoring: Lichen phycobionts present high sensitivity to environmental micropollutants

Abstract

a b s t r a c tBioassays constitute a tool for pollution analysis providing a holistic approach and high-quality indication of the toxicity. Microbioassays allow evaluating the toxicity of many samples, implying lower costs and enabling routine monitoring and pollution control. But tests conducted so far are limited to the use of a small number of taxa. Lichens are excellent bioindicators of pollution with great ecological significance. Studies show that the phycobiont is more sensitive to pollutants than the mycobiont. Phycobiont have features such as adaptation to anhydrobiosis and relatively rapid growth in vitro, making them suitable for microbioassays. Our aim is to determine the sensitivity of phycobionts to the pharmaceutical micropollutants carbamazepine and diclofenac as a preliminary step for the development of a toxicity microbioassay based on phycobionts. Optical dispersion and chlorophyll autofluorescence were used as endpoints of toxicity on two algal species showing that suspensions present cyclic and taxon specific patterns of aggregation. Trebouxia TR9 suspensions present a very high grade of aggregation while Asterochloris erici cells do not. Both micropollutants alter optical properties of the suspensions of both species. No significant alteration of chlorophyll autofluorescence by carbamazepine is observed. A. erici chlorophyll autofluorescence is extremely sensitive to diclofenac but the effect is not dependent on the drug concentration or on the time of exposure. Differently, TR9 only shows punctual chlorophyll alterations. Fluctuations in optical dispersion may indicate changes in the population structure of the species, including reproductive strategy. A. erici seems more sensitive to micropollutants, is better characterized and is available from commercial collections.

Biotechnological applications of lichen phycobionts: fast bioassay of environmental toxicity

“…The main environmental regulatory agencies recommend analyzing the viability of algal cultures to determine the toxic effect of pollutants. Despite aquatic microalgae have been frequently used, due to high reproducibility and sensitivity (Shitanda et al 2009), lichen phycobionts constitute an unexploited option which is highly representative of terrestrial ecosystems (Dominguez-Morueco et al 2014;Traba et al 2017).…”

“…Our microbioassay is not only highly sensitive and fast, but also comes to satisfy the need for efficient environmental monitoring of terrestrial ecosystems (Dominguez-Morueco et al 2014). Furthermore, thanks to this microbioassay, it would be possible to develop a user-friendly kit to evaluate in situ the toxicity of a sample.…”

“…The lack of testing organisms representative of terrestrial habitats in microbioassays has long been highlighted (Catala et al 2009). A good unexploited and unknown option is the use of lichen microalgae (Dominguez-Morueco et al 2014). These have tolerance to desiccation until rehydration allows them to reset their metabolism (Bewley 1979), and are capable of growing outside of symbiosis (Wolseley and Hawksworth 2009).…”

“…These have tolerance to desiccation until rehydration allows them to reset their metabolism (Bewley 1979), and are capable of growing outside of symbiosis (Wolseley and Hawksworth 2009). Many species of lichens are associated with the alga Asterochloris erici (formerly Trebouxia erici) (Skaloud and Peksa 2010) which is sensitive to micropollutants (Dominguez-Morueco et al 2014), may be obtained in large quantities at low cost and tolerates a wide temperature range. The use of biomarkers in phycobionts may help detect the presence of pollutants in a short period of time and at low cost.…”

From Laboratory Tests to the Ecoremedial System: The Importance of Microorganisms in the Recovery of PPCPs-Disturbed Ecosystems

“…PPCPs affect a wide variety of living beings, from the simplest prokaryotes to the most complex eukaryotes (Tables 1 and 2). In the case of bacteria, they can promote changes in the structure and function of the ecosystem, including the primary production of biofilms [16][17][18][19]. Nutrients and micropollutants exert combined effects on the configuration of α and β diversity of fluvial microbial communities.…”