Feasibility of biohydrogen production from industrial wastes using defined microbial co-culture

BACKGROUND: The development of clean or novel alternative energy has become a global trend that will shape the future of energy. In the present study, 3 microbial strains with different oxygen requirements, including Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, were used to construct a hydrogen production system that was composed of a mixed aerobic-facultative anaerobic-anaerobic consortium. The effects of metal ions, organic acids and carbohydrate substrates on this system were analyzed and compared using electrochemical and kinetic assays. It was then tested using small-scale experiments to evaluate its ability to convert starch in 5 L of organic wastewater into hydrogen. For the one-step biohydrogen production experiment, H1 medium (nutrient broth and potato dextrose broth) was mixed directly with GAM broth to generate H2 medium (H1 medium and GAM broth). Finally, Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D of three species microbial co-culture to produce hydrogen under anaerobic conditions. For the two-step biohydrogen production experiment, the H1 medium, after cultured the microbial strains Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, was centrifuged to remove the microbial cells and then mixed with GAM broth (H2 medium). Afterward, the bacterial strain Clostridium acetobutylicum ATCC 824 was inoculated into the H2 medium to produce hydrogen by anaerobic fermentation. RESULTS: The experimental results demonstrated that the optimum conditions for the small-scale fermentative hydrogen production system were at pH 7.0, 35°C, a mixed medium, including H1 medium and H2 medium with 0.50 mol/L ferrous chloride, 0.50 mol/L magnesium sulfate, 0.50 mol/L potassium chloride, 1% w/v citric acid, 5% w/v fructose and 5% w/v glucose. The overall hydrogen production efficiency in the shake flask fermentation group was 33.7 mL/h-1.L-1, and those the two-step and the one-step processes of the small-scale fermentative hydrogen production system were 41.2 mLVh-1.L-1 and 35.1 mL/h-1.L-1, respectively. CONCLUSION: Therefore, the results indicate that the hydrogen production efficiency of the two-step process is higher than that of the one-step process.

Serum Adiponectin and Resistin Levels in Patients with Polycystic Ovarian Syndrome and Their Clinical Implicatlons / 华中科技大学学报（医学）（英德文版）

In this study, serum adiponectin and resistin levels were determined in 46 patients with polycystic ovarian syndrome (PCOS), and their correlation with serum sexual hormones and insulin resistance (IR) were examined. The subjects included 26 obese patients with body mass index (BMI)＞25 and 20 non-obese patients with BMI≤25, with 25 obese and 25 non-obese healthy volunteers without PCOS serving as controls. Serum adiponectin and resistin levels in all subjects were measured, and endocrinal and metabolic indices were also analysed. Our results showed that the serum adiponectin levels in both obese and non-obese PCOS groups were significantly lower than their controls, while the serum resistin levels in obese and non-obese PCOS group were significantly higher than in their controls (P＜0.001). The serum adiponectin level was significantly lower and serum resistin level significantly higher in the non-obese PCOS group as compared with the obese control group (P＜0.05). Serum adiponectin level was negatively correlated with FIN, HOMA-IR, LH and LH/FSH (P＜0.05), but serum resistin level was positively correlated with FIN, HOMA-IR, LH and LH/FSH (P＜0.05). We are led to conclude that PCOS patients have obvious IR, low serum adiponectin and high serum resistin, and adiponectin and resistin might play important roles in the pathogenesis of IR in PCOS patients.