noting that temperature is not the main factor, but higher and longer sunlight
intensity/exposition (warmer seasons) (Khanam and Deb 2016). Additionally, the
removal rate could be species dependent (Escapa et al. 2017), as shown in Table 4.3.
On the other hand, the presence of some compounds such as antibiotics can affect
algae growth and thus phycoremediation rate, for instance, wastewater that contains
residues of tetracycline (an antibiotic) decreases phycoremediation rate, more specifically higher concentration than 30 mg/L eliminates %94% microalgae (Taşkan
2016; Yang et al. 2013; Xiong et al. 2018).
Conventional techniques for industrial wastewater treatments are composed of
sequential steps that include oxidation, co-precipitation and adsorption, lime treatment, ion exchange resins, membrane, among others. Nevertheless, all of these
techniques have technical drawbacks—toxic residual waste, limited efficiency,
operational difficulty, and high operational cost. In this sense, microbial remediation
processes, mainly those that use microalgae (phycoremediation), are the most
promising alternative technologies—“eco-friendly nanofactories” (Madakka et al.
2019).
Phycoremediation is very versatile. It can be applied for wastewater (carbon,
nitrogen, sulfur, etc., degradation), heavy metals (Cd, Cr, Pb, As, etc.), pharmaceuticals paracetamol, salicylic acid, diclofenac, carbamazepine, acetaminophen, ibuprofen, ketoprofen, naproxen, carbamazepine, diclofenac, triclosan, diclofenac,
ibuprofen, paracetamol, metoprolol, carbamazepine, trimethoprim, estrone,
ethinylestradiol, etc. Therefore, phycoremediation should be much more explored
scientifically and technologically.
4.5 High-Added-Value Molecules
There is no consensus on the definition of biorefinery. According to IEA (2008),
which is widely used, “Biorefining is the sustainable processing of biomass into a
spectrum of marketable products and energy.” Thus, microalgae bioprocesses are
very much aligned to the biorefinery concept since there is an inherent and simultaneous production of high-added-value molecules such as phenolics compounds,
fatty acids (long-chain polyunsaturated fatty acids), sterols, proteins including amino
acids and peptides, vitamins, pigments, among others (Andrade et al. 2018).
4.5.1 Volatile Organic Compounds
Volatile organic compounds are compounds that have a high vapor pressure at room
temperature and can be naturally produced by microalgae, mostly, acids, alcohols,
aldehydes, carbonyls, esters, hydrocarbons, ketones, sulfuric compounds, and terpenes (Santos et al. 2016).
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W. Michelon et al.
intensity/exposition (warmer seasons) (Khanam and Deb 2016). Additionally, the
removal rate could be species dependent (Escapa et al. 2017), as shown in Table 4.3.
On the other hand, the presence of some compounds such as antibiotics can affect
algae growth and thus phycoremediation rate, for instance, wastewater that contains
residues of tetracycline (an antibiotic) decreases phycoremediation rate, more specifically higher concentration than 30 mg/L eliminates %94% microalgae (Taşkan
2016; Yang et al. 2013; Xiong et al. 2018).
Conventional techniques for industrial wastewater treatments are composed of
sequential steps that include oxidation, co-precipitation and adsorption, lime treatment, ion exchange resins, membrane, among others. Nevertheless, all of these
techniques have technical drawbacks—toxic residual waste, limited efficiency,
operational difficulty, and high operational cost. In this sense, microbial remediation
processes, mainly those that use microalgae (phycoremediation), are the most
promising alternative technologies—“eco-friendly nanofactories” (Madakka et al.
2019).
Phycoremediation is very versatile. It can be applied for wastewater (carbon,
nitrogen, sulfur, etc., degradation), heavy metals (Cd, Cr, Pb, As, etc.), pharmaceuticals paracetamol, salicylic acid, diclofenac, carbamazepine, acetaminophen, ibuprofen, ketoprofen, naproxen, carbamazepine, diclofenac, triclosan, diclofenac,
ibuprofen, paracetamol, metoprolol, carbamazepine, trimethoprim, estrone,
ethinylestradiol, etc. Therefore, phycoremediation should be much more explored
scientifically and technologically.
4.5 High-Added-Value Molecules
There is no consensus on the definition of biorefinery. According to IEA (2008),
which is widely used, “Biorefining is the sustainable processing of biomass into a
spectrum of marketable products and energy.” Thus, microalgae bioprocesses are
very much aligned to the biorefinery concept since there is an inherent and simultaneous production of high-added-value molecules such as phenolics compounds,
fatty acids (long-chain polyunsaturated fatty acids), sterols, proteins including amino
acids and peptides, vitamins, pigments, among others (Andrade et al. 2018).
4.5.1 Volatile Organic Compounds
Volatile organic compounds are compounds that have a high vapor pressure at room
temperature and can be naturally produced by microalgae, mostly, acids, alcohols,
aldehydes, carbonyls, esters, hydrocarbons, ketones, sulfuric compounds, and terpenes (Santos et al. 2016).
110
W. Michelon et al.