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nanoparticles, thus reduced the toxicity on the microbial enzyme activity. In fact,
reduction of enzyme activity by metal nanoparticles occurred due to binding of
metal to active protein component of enzyme or covering of the active site by the
metal, make the unavailability of active reaction site of enzyme to the substrate
(Vithanage et al. 2017; Kizilkaya and Bayrakli 2005).
Moll et al. (2016) investigated the effects of multi-walled carbon nanotube
(MWCNT), titanium oxide, and cerium oxide on rhizospheric activity in red clove
and found that application of nanomaterial did not affect the nitrogen fixation in red
clove. They measured increase in nitrogen by 8% in soil treated with MWCNT at
3000 ppm. They also observed the colonization of arbuscular mycorrhiza fungi
(AMF) and found no effect of nanoparticles presence on the arbuscular and vesicular colonization. They suggested that the difference in the impact of nanomaterial on
plant and microbial activity is species-specific and one type of nanomaterial can
affect bidirectional (positive or negative) to different strains. The effect of different
types of nanomaterials on enzyme activities and microbial community structure are
given below.
4.5.1 Silver Nanoparticles (Ag NP)
Silver nanoparticles are widely used as antibacterial agents in medicine and food
packing material. The distribution of silver nanomaterials in soil or wastewater also
showed toxicity to nontargeted microbes. It was reported that silver nanoparticles
showed inhibition of DNA transcription and enzyme activity, suppression of respiration in planktonic bacteria (Hwang et al. 2008; Choi et al. 2008; Dror-Ehre et al.
2009; Reinsch et al. 2012). Wigginton et al. (2010) and Yang et al. (2014) reported
that silver nanoparticles directly interacted with enzymes and influenced the microbial community. Reduction in urease activity was also observed at 100 to 1000 ppm
concentration of silver nanoparticles (Shin et al. (2012).
Yang et al. (2013) and Yuan et al. (2013) suggested that silver nanoparticles
could impact on the ecosystem productivity and soil fertility by reducing the activity of functional proteins related to nitrogen cycle in Nitrosomonas europaea. The
detailed information on silver nanoparticles and titanium oxide nanoparticles’
impact on microorganism has been reviewed by Schaumann et al. (2015). Previously,
Schlich et al. (2013) also studied a modal sewage sludge system contained silver
nanoparticles and found that silver nanoparticles showed nano-toxicity toward
microorganism. Schlich and Hund-Rinke (2015) also found that silver nanoparticles
and silver nitrate are toxic toward ammonia-oxidizing bacteria. The silver nanoparticles reduced the soil respiration and enzymatic activity at 0.14 ppm concentration
but at lower concentration 0.0032 to 0.032 ppm did not affect enzymatic activity
(Colman et al. 2013; Hänsch and Emmerling 2010). Shin et al. (2012) reported
reduction in different enzymes like acid phosphatase, β-glucosidase, aryl sulfatase,
dehydrogenase, and fluorescein diacetate hydrolase in sandy soil by citrate-coated
silver nanoparticles. Further, Zhai et al. (2016) suggested that continuous increasing
4 Nano-toxicity to Microbes: Potential Implications of Nanomaterials on Microbial…
nanoparticles, thus reduced the toxicity on the microbial enzyme activity. In fact,
reduction of enzyme activity by metal nanoparticles occurred due to binding of
metal to active protein component of enzyme or covering of the active site by the
metal, make the unavailability of active reaction site of enzyme to the substrate
(Vithanage et al. 2017; Kizilkaya and Bayrakli 2005).
Moll et al. (2016) investigated the effects of multi-walled carbon nanotube
(MWCNT), titanium oxide, and cerium oxide on rhizospheric activity in red clove
and found that application of nanomaterial did not affect the nitrogen fixation in red
clove. They measured increase in nitrogen by 8% in soil treated with MWCNT at
3000 ppm. They also observed the colonization of arbuscular mycorrhiza fungi
(AMF) and found no effect of nanoparticles presence on the arbuscular and vesicular colonization. They suggested that the difference in the impact of nanomaterial on
plant and microbial activity is species-specific and one type of nanomaterial can
affect bidirectional (positive or negative) to different strains. The effect of different
types of nanomaterials on enzyme activities and microbial community structure are
given below.
4.5.1 Silver Nanoparticles (Ag NP)
Silver nanoparticles are widely used as antibacterial agents in medicine and food
packing material. The distribution of silver nanomaterials in soil or wastewater also
showed toxicity to nontargeted microbes. It was reported that silver nanoparticles
showed inhibition of DNA transcription and enzyme activity, suppression of respiration in planktonic bacteria (Hwang et al. 2008; Choi et al. 2008; Dror-Ehre et al.
2009; Reinsch et al. 2012). Wigginton et al. (2010) and Yang et al. (2014) reported
that silver nanoparticles directly interacted with enzymes and influenced the microbial community. Reduction in urease activity was also observed at 100 to 1000 ppm
concentration of silver nanoparticles (Shin et al. (2012).
Yang et al. (2013) and Yuan et al. (2013) suggested that silver nanoparticles
could impact on the ecosystem productivity and soil fertility by reducing the activity of functional proteins related to nitrogen cycle in Nitrosomonas europaea. The
detailed information on silver nanoparticles and titanium oxide nanoparticles’
impact on microorganism has been reviewed by Schaumann et al. (2015). Previously,
Schlich et al. (2013) also studied a modal sewage sludge system contained silver
nanoparticles and found that silver nanoparticles showed nano-toxicity toward
microorganism. Schlich and Hund-Rinke (2015) also found that silver nanoparticles
and silver nitrate are toxic toward ammonia-oxidizing bacteria. The silver nanoparticles reduced the soil respiration and enzymatic activity at 0.14 ppm concentration
but at lower concentration 0.0032 to 0.032 ppm did not affect enzymatic activity
(Colman et al. 2013; Hänsch and Emmerling 2010). Shin et al. (2012) reported
reduction in different enzymes like acid phosphatase, β-glucosidase, aryl sulfatase,
dehydrogenase, and fluorescein diacetate hydrolase in sandy soil by citrate-coated
silver nanoparticles. Further, Zhai et al. (2016) suggested that continuous increasing
4 Nano-toxicity to Microbes: Potential Implications of Nanomaterials on Microbial…