Department of Biotechnology

About: Department of Biotechnology is a government organization based out in New Delhi, India. It is known for research contribution in the topics: Population & Silver nanoparticle. The organization has 4800 authors who have published 5033 publications receiving 82022 citations.

Optimization of physicochemical parameters for phenol biodegradation by Candida tropicalis PHB5 using Taguchi Methodology

Abstract: The Taguchi orthogonal array (OA) design of experiments methodology, a quality optimization tool, was used to improve the phenol biodegradation potential of the yeast Candida tropicalis PHB5. At three levels, an OA was selected to analyze the effects of the different physicochemical process factors. Experiments were undertaken to confirm the effectiveness of this method and the main factors affecting the growth of C. tropicalis on phenol and its subsequent degradation were found, together with the optimal factor levels. Predicted results showed that biomass yield could be increased from 1,051.96 to 2,495.74 mg/l and the subsequent amount of phenol degraded could be increased from 879.42 to 2,386.43 mg/l. Based on Taguchi methodology, an overall enhancement of growth by 137.24% and phenol degradation by 171.49% could be attained. Validation experiments showed that the growth and phenol biodegradation was significantly improved by up to 132.4% and 165.64%, respectively.

Modulation of α-synuclein aggregation by dopamine in the presence of MPTP and its metabolite.

Abstract: The neurotransmitter dopamine has been shown to inhibit fibrillation of α-synuclein by promoting the formation of nonamyloidogenic oligomers. Fibrillation of α-synuclein is accelerated in the presence of pesticides and the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The aim of this study was to determine whether dopamine continues to have an adverse effect on the fibrillation of α-synuclein in the presence of MPTP and its metabolite 1-methyl-4-phenylpyridinum ion (MPP(+) ). We also attempted to answer the ambiguous question of whether conversion of MPTP to MPP(+) is required for the fibrillation of α-synuclein. For this, α-synuclein was incubated in the presence of MPTP and MPP(+) along with dopamine. The fibrillation of α-synuclein was monitored by Thioflavin T fluorescence and immunoblotting. The morphology of the aggregates formed was observed using scanning electron microscopy. The concentrations of the neurotoxin and its metabolite were estimated by reverse phase HPLC. We found definitive evidence that the conversion of MPTP to MPP(+) is not required for aggregation of α-synuclein. MPP(+) was found to accelerate the rate of α-synuclein aggregation even in the absence of components of mitochondrial complex I. In contrast to the effect of dopamine on the aggregation of α-synuclein alone, in the presence of MPTP or MPP(+) , the aggregates formed are Thioflavin T-positive and amyloidogenic. Thus, the effect of dopamine on the nature of aggregates formed in case of α-synuclein alone and in the presence of MPTP/MPP(+) is different.

Ion-water wires in imidazolium-based ionic liquid/water solutions induce unique trends in density

Abstract: Ionic liquid/water binary mixtures are rapidly gaining popularity as solvents for dissolution of cellulose, nucleobases, and other poorly water-soluble biomolecules. Hence, several studies have focused on measuring the thermophysical properties of these versatile mixtures. Among these, 1-ethyl-3-methylimidazolium ([emim]) cation-based ILs containing different anions exhibit unique density behaviours upon addition of water. While [emim][acetate]/water binary mixtures display an unusual rise in density with the addition of low-to-moderate amounts of water, those containing the [trifluoroacetate] ([Tfa]) anion display a sluggish decrease in density. The density of [emim][tetrafluoroborate] ([emim][BF4])/water mixtures, on the other hand, declines rapidly in close accordance with the experimental reports. Here, we unravel the structural basis underlying this unique density behavior of [emim]-based IL/water mixtures using all-atom molecular dynamics (MD) simulations. The results revealed that the distinct nature of anion-water hydrogen bonded networks in the three systems was a key in modulating the observed unique density behaviour. Vast expanses of uninterrupted anion-water-anion H-bonded stretches, denoted here as anion-water wires, induced significant structuring in [emim][Ac]/water mixtures that resulted in the density rise. Conversely, the presence of intermittent large water clusters disintegrated the anion-water wires in [emim][Tfa]/water and [emim][BF4]/water mixtures to cause a monotonic density decrease. The differential nanostructuring affected the dynamics of the solutions proportionately, with the H-bond making and breaking dynamics found to be greatly retarded in [emim][Ac]/water mixtures, while it exhibited a faster relaxation in the other two binary solutions.

Lipid production and molecular dynamics simulation for regulation of accD gene in cyanobacteria under different N and P regimes.

Abstract: Microalgae grown under different nutrient deficient conditions present a good source of natural lipids with applications for several types of biofuels. The expression of acetyl-CoA carboxylase gene can further provide an insight to the mechanisms leading to enhanced lipid production under such stresses. In this study, two nutrients viz. nitrogen and phosphorus were modulated to see its effect on lipid productivity in selected cyanobacteria and its correlation with Accase followed by molecular dynamics simulation. Selected cyanobacteria viz. Oscillatoria sp. (SP8), Anabaena sp. (SP12), Anabaena sp. (SP13), Microcoleus sp. (SP18), and Nostoc sp. (SP20) varied in their ability to accumulate lipids which ranged from a lowest of 0.13% in Anabaena sp. (SP13) to the maximum of 7.24% in Microcoleus sp. (SP18). Microcoleus sp. (SP18) also recorded highest lipid accumulation at both N (6 mM NaNO3) and P (0.20 mM K2HPO4) limiting conditions. The overall expression of accD was found to be upregulated in both Oscillatoria sp. (SP8) and Microcoleus sp. (SP18) for all nitrogen concentrations but was differentially regulated with both positive and negative induction under phosphorus stress conditions. Maximum induction was observed in Microcoleus sp. (SP18) at 0.20 mM K2HPO4. The obtained 3D structure of SP8 protein (21.8 kDa) showed six alpha helices, while SP18 protein (16.7 kDa) exhibited four alpha helices and four beta sheets. The phi (ϕ)/psi(ψ) angles of the amino acid residues observed in Ramachandran plot analysis showed that both SP8 and SP18 proteins were highly stable with more than 90% amino acids in allowed regions. The molecular dynamics simulation results also indicated the stability of ligand-bound protein complexes. It has been demonstrated that cyanobacterial isolates are affected differently by nutrient limitation leading to variation in their lipid productivity. The same has been revealed by the behavior of accD gene expression which was regulated more by nutrients concentrations rather than the organism. However, the ligand-bound protein complexes were stable throughout MD simulations.