Table 1.

Nanomaterials synthesized by bacteria.

Microorganism	Culture Conditions (Synthesis Time)	Nanomaterial	Characterization	Biosynthetic Pathway	Application	Ref.
Bacillus subtilis	Enrichment medium, 35 °C, stirred at 170 rpm + 4 mM Na2SeO3 (48 h)	Se NPs	50–400 nm; spherical regular morphology; 100 nm uniform single-crystalline; nanowires	Reduction mechanism of SeO32− ions to Se0 is yet to be elucidated	H2O2 sensoristic device	[19]
Streptomyces minutisclero-ticus M10A62	5 g of wet bacterial biomass from 120 h cell culture + 1 mM Na2SeO3, stirred at 200 rpm (72 h)	Se NPs	10–250 nm; spherical shape; crystalline; ζ-potential −19.1 mV	Extracellular synthesis not described	Anti-biofilm, antioxidant activity, antiviral activity against Dengue virus; anti-proliferative activity against HeLa and HepG2 cell lines	[21]
Pantoea agglomerans strain UC-32	1% (v/v) of an overnight cell culture in tryptic soy broth + 1 mM Na2SeO3, 25 °C (24 h)	Se NPs	<100 nm; spherical shape; amorphous form size vary with culture time (10–24 h);	Intracellular reduction of Se (IV) to Se (0) and subsequent excretion	High antioxidant activity (when stabilized with L-cysteine)	[29]
Streptomyces bikiniensis strain Ess_amA-1	1 mL fresh bacteria inoculums (OD600 = 0.5 a.u.) in international Streptomyces Project 2 medium + 1 mM SeO2, 30 °C, stirred at 150 rpm (48 h)	Se NPs	600 nm length, 17 nm diameter	Possible involvement of proteins/enzymes in SeO2 reduction nucleation, growth, stabilization of nanorods	In vitro anticancer activity against human breast adenocarcinoma cell line and human liver carcinoma cell line	[32]
Escherichia coli DH5α	10 h culture, resuspended in sterile distilled water + 1 mM HAuCl4, room temperature (120 h)	Au NPs	25 ± 8 nm; spherical shape; crystalline form (face centered cubic phase)	Extracellular synthesis possibly modulated by sugars or enzymes present onto bacteria surface	Direct electro-chemistry of hemoglobin	[20]
Shewanella oneidensis MR-1	Washed cell pellet from a 24 h cell culture + 1 mM HAuCl4, 30 °C, stirred at 200 rpm (48 h)	Au NPs	12 ± 5 nm; spherical shape, capping proteins easily removable but not identified	Extracellular synthesis possible electron shuttle-based enzymatic reduction of ionic Au3+ to Au0	No antibacterial properties/annealing and thin film formation	[23]
Nocardiopsis sp. MBRC-48	Cell-free supernatant (from a 96 h cell culture) + 0.9 mM HAuCl4, incubated in the dark, 35 °C, stirred at 180 rpm (48 h)	Au NPs	11.57 ± 1.24 nm; spherical shape; face centered cubic; polydispersed without significant structure	Extracellular synthesis using the cell free supernatant, proteins, enzymes and metabolites	High antimicrobial activity against Staphylococcus aureus and Candida albicans, antioxidant activity and cytotoxic activities	[25]
Brevibacterium casei	1 g of wet bacterial biomass + 1 × 10−3 M AgNO3 + 1 × 10−3 M HAuCl4, 37 °C, stirred at 200 rpm (24 h)	Au and Ag NPs	Ag 10–50 nm, Au, 0–50 nm; spherical shape, crystalline form (face centered cubic phase)	Intracellular synthesis, possible roles of NADH-dependent nitrate reductase (for Ag NPs) and α-NADPH-dependent sulfite reductase (for Au NPs)	Anti-coagulant properties	[31]
Shewanella oneidensis MR-1	∼3–5 g of wet bacterial biomass from 24 h cell culture + 1 mM AgNO3, 30 °C stirred at 200 rpm (48 h	Ag NPs	∼2–11 nm spherical shape; crystalline form; ζ-potential = −16.5 mV	Extracellular synthesis by secreted factors (e.g., NADH-dependent reductases, quinines, soluble electron-shuttles)	Antibacterial activity against Escherichia coli and Bacillus subtilis	[24]
Lyngbya majuscula (CUH/Al/MW-150)	100 mg of fresh weight biomass + 9 mM Ag(I) solution (pH 4) incubated in the dark, room temperature (72 h)	Ag NPs	∼5–50 nm; spherical shape, crystalline form (face-centered cubic), smooth surface morphology, both (sonication) ζ-potential = −35.2 mV	Extracellular and intracellular synthesis not described	Effective antibacterial activity against Pseudomonas aeruginosa; appreciable anti-proliferative effect on leukemic cells, especially on the REH cell line	[26]
Streptomyces s. Al-Dhabi-87	Broth-free cell pellets (14-days cell culture) in sterile distilled water for 1 h; cell removed from the suspension + 1–5 mM AgNO3, 37 °C (48 h)	Ag NPs	20–50 nm; spherical shape	Extracellular synthesis possibly via hydrophilic and hydrophobic small metabolites attached on the bacteria cell wall	In vitro antimicrobial activity against Bacillus subtilis, Enterococcus faecalis, Staphylo-coccus epi-dermidis, and multidrug resistant Staphylococcus aureus strain	[27]
Bacillus licheniformis	2 g of wet bacterial biomass + 1 mM AgNO3, 37 °C, stirred at 200 rpm (24 h)	Ag NPs	40 nm to 50 nm	N/A	Possible application as anti-proliferative and anti-migration agent e.g., against diabetic retinopathy, neoplasia and rheumatoid arthritis	[30]
Escherichia coli K12 (ATCC 29181)	Bacterial culture (OD600 = 0.6 a.u.), Luria Bertani medium + 3 mM CdCl2 + 6 mM Na3C6H5O7 + 0.8 mM Na2TeO3, 8 mM C4H6O4S + 26 mM NaBH4, 37 °C, stirred at 200 rpm (24 h)	CdTe QDs	∼2–3 nm; uniform size, cubic crystals; strong fluorescence emission shift with increasing quantum dots size, capping proteins were not identified but enhance QDs biocompatibility; ζ-potential = −19.1 mV	Extracellular synthesis possibly via protein-assisted nucleation biosynthesis	Possible application in vitro cell imaging (demonstrated on HeLa cells) and bio-labeling	[22]
Acetobacter xylinus GIM1.327	Static culture in polysaccharides enriched medium, 30 °C (120 h)	Bacterial nanocellulose nanofibrils impregnated with Ag-NPs	Nanoporous three-dimensional network structure with a random arrangement of ribbon-shaped microfibrils without any preferential orientation; 2 to 100 nm (Ag NPs)	Intracellular-extracellular synthesis via enzymes glucokinase, phosphoglucomutase, UDPG, pyro-phospho-rylase and cellulose synthase	In vitro pH-responsive antimicrobial activity against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538, Bacillus subtilis ATCC 9372 and Candida albicans CMCC(F) 98001	[28,35]
Acetobacter xylinum	N/A	Ag NPs and bacterial nano-paper composite	AgNPs 10–50 nm	Intracellular-extracellular synthesis of bacterial nanocellulose via enzymes glucokinase, phosphoglucomutase, UDPG, pyro-phospho-rylase and cellulose synthase AgNPs synthesis via direct chemical reduction of Ag+ mediated by baring hydroxyl groups of bacterial nanocellulose	Optical detection of cyanide ion and 2-mercaptobenzo-thiazole in water samples	[35,36]
Acetobacter xylinum	Static culture containing 50 g/L glucose, 5 g/L yeast extract, 5 g/L (NH4)2SO4, 4 g/L KH2PO4 and 0.1 g/L MgSO4·7H2O, 28 °C (366 h)	Nanocompositesof bacterial nanocellulose with AgNP, Au-NPs CdSe@ZnS quantum dots functionalized with biotinylated antibodies, aminosilica-coated lanthanide-doped up-conversion NPs	(bacterial nanocellulose) 45 ± 10 nm (fiber mean diameter); estimated length > 10 μm	Intracellular-extracellular synthesis via enzymes glucokinase, phosphoglucomutase, UDPG, pyro-phospho-rylase and cellulose synthase	Optical detection of methimazole, thiourea, cyanide, and iodide and Escherichia coli; possible uses in analytes pre-concentration platform	[35,37]
Bacillus marisflavi GS3	200 mg biomass + 2.4 × 10−5 M graphene oxide dispersion mixture, 37 °C (72 h)	Reduced graphene oxide nanosheets	~4.3 nm (average thickness), significant reduction of GO (assessed by XRD analysis); several layers stacked on top of one another like silky sheets of paper (SEM image)	Extracellular synthesis not described	Inhibition of cell viability, reactive oxygen species (ROS) generation, and membrane integrity alteration in MCF-7 cell line	[33]
Magnetospirillum magneticum AMB-1 (Genetically modified)	Anaerobically grown in 5 ml/L of Wolfe’s mineral solution (without iron), + 5 mM KH2PO4 + 10 mM NaNO3 + 0.85 mM C2H3NaO2 + 0.2 mM C6H8O6 + 2.5 mM C4H6O6 + 0.6 mM Na2S2O3, pH 6.9; cell pellets were resuspended in 20 mM HEPES + 1 mM EDTA + 8% glycerol + 0.9% NaCl, pH 7.5	Magnetosome (bio-mineralized iron-oxide nanoparticles coated by a biological membrane)	Magnetosome membrane modified with Venus-RGD protein as specific and sensitive molecular imaging probe	Natural mechanism of magneto-somes formation (biomineralization) + genetic modification for Venus protein- RGD peptide expression	Contrast agent for in vivo magnetic resonance-based molecular imaging	[47]
Magnetospirillum magneticum strain AMB-1	Micro-anaerobically grown in a similar culture medium of [47]	Whole inactive magnetotactic bacteria γ-Fe2O3 magnetosomes chains individual γ-Fe2O3 magnetosomes	Magnetosomes chains (length) ∼150 or ∼300 nm; individual magnetosomes mean size ∼45 nm; well-crystallized monodomain with a ferromagnetic behavior at physiological temperature	Natural mechanism of magneto-somes formation + genetic modification for Venus protein- RGD peptide expression	Antitumoral activity against MDA-MB-231 breast cancer cells under alternating magnetic field stimulation	[48]
Magnetospirillum gryphiswaldense strain MSR-1	Micro-anaerobically grown in a similar culture medium of [47] and [48] + 50μM Fe(III) citrate	Chains of magnetosomes	Magnetosome membrane modified with Red-emitting Click Beetle luciferase (CBR)	Natural mechanism of magneto-somes formation + genetic modification for red-emitting click beetle luciferase expression	Toxicity assay on microfluidic chip for the detection of toxicity effect on membrane by DMSO and TCDCA	[49]