Hyperthermophilic Clostridium sp. N-4 produced a glycoprotein biosurfactant that enhanced recovery of residual oil at 96 °C in lab studies.

Biosurfactant producing hypethermophilic microorganisms are essentially required for Microbial Enhanced Oil Recovery (MEOR) from high temperature oil reservoirs (above 90 °C). In the present study, biosurfactant producing Clostridium sp. N-4, optimally growing at 96 °C was isolated from a high temperature oil reservoir. Effect of pH, temperature and salinity on production and activity of N-4 biosurfactant was investigated. Biosurfactant produced by N-4 was partially purified by acid precipitation, characterized using FT-IR spectroscopy; and evaluated for its ability to enhance oil recovery in sand pack studies. The strain N-4 produced biosurfactant over a wide range of pH (5.0-9.0) and salinity (0-13%) at high temperature (80-100 °C) and optimally at pH 7, 96 °C and 4% salinity. N-4 biosurfactant was active at 37-101 °C; pH, 5-10 and salinity of 0-12 % (w/v). N-4 biosurfactant, characterized as glycoprotein reduced the surface tension of water by 32 ± 0.4 mN/m at critical micelle concentration of 100 µg/ml. N-4 biosurfactant mobilized 17.15% of residual oil saturation in sand pack studies. Similarly, the strain N-4 also recovered 36.92% of the residual oil in sand pack studies under the conditions mimicking the environment of depleted high temperature oil reservoir. Thus, the biosurfactant producing Clostridium sp. N-4 was identified as a suitable agent for enhanced oil recovery from high temperature oil reservoirs.

Impact of three different daily doses of vitamin D3 supplementation in healthy schoolchildren and adolescents from North India: a single-blind prospective randomised clinical trial.

In India, there is a lack of information about the adequate daily dose of vitamin D3 supplementation in school children. Hence, we undertook this study to evaluate the adequacy and efficacy of different doses of vitamin D3 in schoolchildren. A total of 1008 vitamin D-deficient (VDD) children, aged 6-16 years with serum 25-hydroxyvitamin D (25(OH)D) levels <50nmol/l, were cluster randomised into three groups (A-344, B-341 and C-232) for supplementation (600, 1000 and 2000 IU daily) of vitamin D3 under supervision for 6 months. Of the 1008 subjects who completed the study, 938 (93 %) were compliant. Baseline and post-supplementation fasting blood and urine samples were evaluated for Ca, phosphates, alkaline phosphatase, 25(OH)D and parathormone and urine Ca:creatinine ratio. The mean age of the subjects was 11·7 (sd 2·4) years, and the overall mean baseline serum 25(OH)D level was 24·3 (SD 9·5)nmol/l. Post-supplementation rise in serum 25(OH)D in compliant group was maximum with 2000 IU (70·0 (SD 30·0)nmol/l), followed by 1000 IU (46·8 (SD 22·5)nmol/l) and 600 IU (36·5 (SD 18·5)nmol/l), and serum 25(OH)D levels of ≥50nmol/l were achieved in 71·5, 81·8 and 92·9 % by groups A, B and C, respectively. Secondary hyperparathyroidism decreased from 31·7 to 8·4 % post-supplementation. Two participants developed hypercalciuria, but none developed hypercalcaemia. Children with VDD benefit maximum with the daily supplementation of 2000 IU of vitamin D3. Whether recommendations of 400 IU/d by Indian Council of Medical Research or 600 IU by Indian Academy of Pediatrics or Institute of Medicine would suffice to achieve vitamin D sufficiency in children with VDD remains debatable.

A randomised controlled trial comparing the efficacy of micellised and fat-soluble vitamin D3 supplementation in healthy adults.

Nanoemulsion formulation of vitamin D3 have been shown to have better bioavailability than the coarse emulsion preparation in vitro and in vivo animal studies. In the absence of randomised trial in humans, comparing the efficacy of nanotechnology-based miscellised vitamin D3 over conventional vitamin D3, we undertook this study. A total of 180 healthy adults were randomised to receive either micellised (DePura, group A) or conventional vitamin D3 (Calcirol, group B) at a monthly dose of 60 000 IU (1500µg) for 6 months. The outcome parameters were serum 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH), Ca, phosphate, alkaline phosphatase and urinary Ca:creatinine ratio. A total of eighty-nine subjects in group A and seventy-seven in group B completed the trial. Subjects in both the groups had a significant increase in their serum 25(OH)D levels following supplementation (group A: 21·5 (sd 10·9) to 76·7 (sd 18·8) nmol/l (P<0·001); group B: 22·8 (sd 10·4) to 57·8 (sd 16·0) nmol/l (P<0·001)). Participants in micellised group had an additional increase of 20·2 (95 % CI 14·0, 26·4) nmol/l in serum 25(OH)D levels (P<0·001). The difference between the groups was 17·5 (95 % CI 11·8, 23·1) nmol/l, which remained statistically significant (P<0·001) even after adjustment for age and sex. Significant decline in mean serum PTH was observed in both the groups. No hypercalcaemia or hypercalciuria was noted. Although supplementation with both the preparations resulted in a significant rise in serum 25(OH)D levels, micellised vitamin D3 appeared to be more efficacious in achieving higher levels of serum 25(OH)D.

Association of insulin-like growth factor-1 and IGF binding protein-3 with 25-hydroxy vitamin D in pre-pubertal and adolescent Indian girls.

BACKGROUND: There is a high prevalence of vitamin D deficiency (VDD) in India. Molecular mechanisms suggest a strong relationship between vitamin D and growth factors. However, there is a paucity of literature with regard to a relationship between insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3) and vitamin D particularly in subjects with VDD. The objective of the study was to assess the relationship between growth factors and serum vitamin D-parathormone (PTH) status in school girls and study the impact of vitamin D supplementation on growth factors in pre-pubertal girls with VDD. METHODS: Our study subjects were apparently healthy school girls aged 6-18 years. The baseline height, weight, body mass index (BMI), pubertal status, serum 25-hydroxy vitamin D (25OHD), PTH, IGF-1 and IGFBP-3 were assessed in 847 girls aged 6-18 years and in 190 pre-pubertal girls with VDD following supplementation. RESULTS: The mean age, BMI and serum 25OHD of girls were 11.5±3.2 years, 18.7±4.8 kg/m2 and 9.9±5.6 ng/mL, respectively. VDD was observed in 94.6% of girls. Unadjusted serum IGF-1 levels and IGF-1/IGFBP-3 molar ratio were significantly higher in girls with severe VDD as compared to girls with mild-to-moderate VDD. However, these differences disappeared when adjusted for age, height or sexual maturation. The serum IGF-1 and IGFBP-3 levels increased significantly post supplementation with vitamin D. CONCLUSIONS: There were no differences in serum IGF-1 levels and the IGF-1/IGFBP-3 molar ratio among VDD categories when adjusted for age, height and sexual maturation in girls. Vitamin D supplementation resulted in a significant increase in serum IGF-1 levels in VDD pre-pubertal girls.

Development of a microbial process for the recovery of petroleum oil from depleted reservoirs at 91-96°C.

A consortium of bacteria growing at 91°C and above (optimally at 96°C) was developed for the recovery of crude oil from declining/depleted oil reservoirs having temperature of more than 91°C. PCR-DGGE-Sequencing analysis of 16S rRNA gene fragments of NJS-4 consortium revealed the presence of four strains identified as members of the genus Clostridium. The metabolites produced by NJS-4 consortium included volatile fatty acids, organic acids, surfactants, exopolysaccarides and CO2, which reduced viscosity, emulsified crude oil and increased the pressure that facilitated displacement of emulsified oil towards the surface. NJS-4 enhanced oil recovery by 26.7% and 10.1% in sand pack trials and core flood studies respectively in optimized nutrient medium comprised of sucrose and sodium acetate as carbon/energy source and urea as nitrogen source (pH 7-9, 96°C, and 4% salinity). Nutrient medium for MEOR was constituted using commercial grade cheap nutrients to improve the economic viability of MEOR process.