Nanotechnology in Bioprocess Development …
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production from waste cooking oil. The combination of both NPs showed an excellent catalytic efficiency, resulting in biodiesel yield of 98.95%, which was attained
with 0.7 g of CaO and 0.5 g of MgO nanoparticles (Tahvildari et al. 2015).
In another study, Dantas et al. (2017) reported on the influence of copper-magnetic
nanoferrites on methyl transesterification of soybeans oil and demonstrated up to
85% enhancement in the biodiesel yield. Furthermore, acid-functionalized magnetic
nanocatalyst was evaluated for catalytic potential in the transesterification of glyceryl trioleate to biodiesel (Dantas et al. 2017). The acid-functionalized nanoparticles
(sulfamic silica-coated crystalline Fe/Fe 3 O 4 core–shell magnetic nanoparticles) additives showed notable catalytic activity, with high biodiesel conversion of more than
95% (Wang et al. 2015). Also, Chiang et al. (2015) used functionalized nanoparticles
(Fe 3 O 4 @silica core–shell nanoparticles) for microalgae oil conversion to biodiesel
and obtained a high percentage yield (97.1%). The use of calcite-Au nanoparticles for biodiesel production has been evaluated by Bet-Moushoul et al. (2016).
These authors recorded a conversion value of 97.5% at 3% calcite-Au nanoparticles catalyst loading. The application of nanoparticles in biodiesel production has
showed an enhanced substrate conversion, increased productivity, catalyst recovery
and reusability. Various nanoparticles have been employed as a biocatalyst for the
enhancement of biodiesel production (Table 1).
2.2 Bioethanol Production
Bioethanol is produced when microbes such as Saccharomyces cerevisiae or
Zymomonas mobilis that metabolize fermentable sugars under microaerophilic or
anaerobic conditions to produce ethanol and CO 2 (Baeyens et al. 2015). Different
attempts have been made to improve the bioethanol fermentation process (Kim et al.
2016). Metallic nanoparticles in fermentation process nutrient formulation have
recently been identified as advantageous in stimulating and promoting the bioactivity of ethanol-producing microorganisms and fermentation productivity (Demirel
and Scherer 2011; Miazek et al. 2015; Pádrová et al. 2015; Kim et al. 2016). Kim et al.
(2014) supplemented six different nanoparticles to enhance bioethanol production
in syngas fermentation using Clostridium ljungdahlii. The aforementioned study
revealed a 34.5, 166.1, and 29.1% increase in the levels of biomass, ethanol, and
acetic acid production, respectively due to supplementation with nanoparticles (Kim
et al. 2014). These enhancements were ascribed to enhanced gas–liquid mass transfer
by methyl and isopropyl hydrophobic surface modification on the silica NPs (Kim
et al. 2014). The effects could also be attributed to improved metabolic and enzymatic activities, buffering capacity and oxidation–reduction potential (ORP) of the
nano-system.
In addition, Sanusi et al. (2019) assessed the potential of nine different metallic
oxide nanoparticles to improve bioethanol production using S. cerevisiae. Of these
metallic nanooxides, NiO NPs, Fe 3 O 4 NPs, CuO NPs, CoO and ZnO NPs inclusions showed desirable catalytic potentials, with Fe 3 O 4 NPs inclusion producing the
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production from waste cooking oil. The combination of both NPs showed an excellent catalytic efficiency, resulting in biodiesel yield of 98.95%, which was attained
with 0.7 g of CaO and 0.5 g of MgO nanoparticles (Tahvildari et al. 2015).
In another study, Dantas et al. (2017) reported on the influence of copper-magnetic
nanoferrites on methyl transesterification of soybeans oil and demonstrated up to
85% enhancement in the biodiesel yield. Furthermore, acid-functionalized magnetic
nanocatalyst was evaluated for catalytic potential in the transesterification of glyceryl trioleate to biodiesel (Dantas et al. 2017). The acid-functionalized nanoparticles
(sulfamic silica-coated crystalline Fe/Fe 3 O 4 core–shell magnetic nanoparticles) additives showed notable catalytic activity, with high biodiesel conversion of more than
95% (Wang et al. 2015). Also, Chiang et al. (2015) used functionalized nanoparticles
(Fe 3 O 4 @silica core–shell nanoparticles) for microalgae oil conversion to biodiesel
and obtained a high percentage yield (97.1%). The use of calcite-Au nanoparticles for biodiesel production has been evaluated by Bet-Moushoul et al. (2016).
These authors recorded a conversion value of 97.5% at 3% calcite-Au nanoparticles catalyst loading. The application of nanoparticles in biodiesel production has
showed an enhanced substrate conversion, increased productivity, catalyst recovery
and reusability. Various nanoparticles have been employed as a biocatalyst for the
enhancement of biodiesel production (Table 1).
2.2 Bioethanol Production
Bioethanol is produced when microbes such as Saccharomyces cerevisiae or
Zymomonas mobilis that metabolize fermentable sugars under microaerophilic or
anaerobic conditions to produce ethanol and CO 2 (Baeyens et al. 2015). Different
attempts have been made to improve the bioethanol fermentation process (Kim et al.
2016). Metallic nanoparticles in fermentation process nutrient formulation have
recently been identified as advantageous in stimulating and promoting the bioactivity of ethanol-producing microorganisms and fermentation productivity (Demirel
and Scherer 2011; Miazek et al. 2015; Pádrová et al. 2015; Kim et al. 2016). Kim et al.
(2014) supplemented six different nanoparticles to enhance bioethanol production
in syngas fermentation using Clostridium ljungdahlii. The aforementioned study
revealed a 34.5, 166.1, and 29.1% increase in the levels of biomass, ethanol, and
acetic acid production, respectively due to supplementation with nanoparticles (Kim
et al. 2014). These enhancements were ascribed to enhanced gas–liquid mass transfer
by methyl and isopropyl hydrophobic surface modification on the silica NPs (Kim
et al. 2014). The effects could also be attributed to improved metabolic and enzymatic activities, buffering capacity and oxidation–reduction potential (ORP) of the
nano-system.
In addition, Sanusi et al. (2019) assessed the potential of nine different metallic
oxide nanoparticles to improve bioethanol production using S. cerevisiae. Of these
metallic nanooxides, NiO NPs, Fe 3 O 4 NPs, CuO NPs, CoO and ZnO NPs inclusions showed desirable catalytic potentials, with Fe 3 O 4 NPs inclusion producing the