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Volume 2
Environment Pollution and Climate Change
ISSN: 2573-458X
Climate Change 2018 &
Global ENVITOX 2018
October 04-06, 2018
October 04-06, 2018
London, UK
16
th
Annual Meeting on
Environmental Toxicology and Biological Systems
&
5
th
World Conference on
Climate Change
JOINT EVENT
Directed evolution, biotechnology and in silico analysis of reaction centre proteins formicroorganisms
and biomimetic-based biosensors in environmental toxicity monitoring
Maria Teresa Giardi
1,2
, Gianni Basile
2
and
Mehmet Turemis
2
1
CNR-Institute of Crystallography, Italy
2
Biosensor Srl, Italy
T
ons of chemical compounds derived from human and industrial activities are incessantly threatening our environment.
Current approaches for monitoring of pollutants include precise and accurate assessment of individual compounds
by chemical analyses, which are however unable to provide information about bioavailability, effect on living organisms,
and synergistic or antagonistic behaviour in mixtures, thus requiring combination with biomarker assays and ecosystem
monitoring. These methodology strategy is time and labour intensive, demands ex-situ collection at individual locations and
extensive sample preparation, and has elevated costs depending on the complexity.
To overcome these challenges, biosensor and bioassay technology can furnish advanced devices for water monitoring with
greater efficiency. Indeed, integrated, cost-effective, easy to use, and fast biosensors can be projected to characterize the
extent of pollution at relevant spatio-temporal scales and in terms of ecological effects. Despite this great potential, most
of the published works focused on analyses of fresh water, mainly because of the highly demanding working environment
that seawater constitutes. To face the challenges posed by real environments, biosensors need to be fully automated, very
robust (resistant to physical impacts, high corrosion, and biofouling), drift-free or with accurate calibration, with minimal
power consumption, user-friendly, and enough sensitive to measure pollutants at very low concentrations. Several examples
of biosensor development for marine measurements of eutrophication, pesticides, anti-biofouling agents, polycyclic aromatic
hydrocarbons, endocrine disruptors, trace metals, organism detection and algal toxins have been described in literature.
Algal biosensors react very broadly to toxicity and their detection mechanism frequently relies on measurement of the
photosynthetic activity caused by 33% of pesticides actually in the market. Biosensing applications of photosynthetic organisms
are based on the inhibition of the electron transfer occurring after a few minutes exposure of photosystem II (PSII) to certain
pollutants, or to adverse physicochemical conditions changing the local chemical equilibrium. Indeed, when pollutants such
as photosynthetic pesticides are present and encounter the photosystem, they can bind the reaction centre D1 protein and
directly or indirectly inhibit the transport of electrons from the primary acceptor, plastoquinone A (QA), to the secondary
quinone (QB) along the photosynthetic chain. This inhibition results in a variation of PSII fluorescence emission in a pollutant
concentration-dependent manner that can be monitored by optical transduction. Based on this approach, several microalgal
biosensors have been designed for pesticide and heavy metal detection in fresh water. However, hyper-saline conditions present
in marine environment and stress conditions during environmental monitoring may affect the photosynthetic process resulting
in significant changes in the bioassay performance. Herein we present the development of an optical bioassay for detection of
photosynthetic pesticides from different chemical classes in real water samples by exploiting various green microalgae strains.
Therefore, the main objectives were to select the most appropriate microalgae strains to achieve stability and adaptability into
real matrices, and to develop a bioassay integrated with portable fluorescence instrumentation allowing pesticide detection at
relevant environmental concentrations. Several microalgae species from Chlorophyceae, Trebouxiophyceae, Dinoflagellates,
Diatoms and Eustigmatophyceae groups with different marine and non-marine origins, including fresh water and soil, were
analysed. Lipid content of selected microalgae suggested that
C. mirabilis
and symbiotic associations between
C.vulgaris
and
protozoa were the microorganisms with higher potential to acclimate to high salinity environments being mainly constituted
by unsaturated lipids involved in responses to several environmental stresses.
Maria Teresa Giardi et al., Environ Pollut Climate Change 2018, Volume 2
DOI: 10.4172/2573-458X-C1-002