The rapidly expanding market for biodiesel has increased the supply and reduced the cost of glycerol, making it an attractive sustainable feed stock for the fuel and chemical industry. Glycerol-based biorefinery is the microbial fermentation of crude glycerol to produce fuels and chemicals. A major challenge is to obtain microbes tolerant to inhibitors such as salts and organic solvents present in crude glycerol. Microbial screening was attempted to isolate novel strain capable of growing on crude glycerol as a sole carbon source. The newly isolated bacteria, identified as nonpathogenic Kluyvera cryocrescens S26 could convert biodiesel-derived crude glycerol to ethanol with high yield and productivity. The supplementation of nutrients such as yeast extract resulted in distinguished enhancement in cell growth as well as ethanol productivity under anaerobic condition. When glycerol fermentation is performed under microaerobic condition, there is also a remarkable improvement in cell growth, ethanol productivity and yield, compared with those under strict anaerobic condition. In batch fermentation under microaerobic condition, K. cryocrescens S26 produced 27 g/l of ethanol from crude glycerol with high molar yield of 80% and productivity of 0.61 g/l/h.

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Carbon nanotubes (CNTs) have emerged recently as superior adsorbent materials for the removal of recalcitrant pollutants. The potential of combining the sorption capability of CNTs with bacterial degradation for pollutant removal, however, necessitates further investigation of the mechanisms of CNTs' toxicity towards bacterial cells. In this study, we used a panel of stress-responsive recombinant Escherichia coli bioluminescence bacterial strains to explore the possible mechanisms of toxicity of multiwalled carbon nanotubes (MWCNTs). The effects of MWCNTs on markers of oxidative stress, protein, DNA, and membrane damage enabled the exposition of some of the mechanisms of their antimicrobial properties. Using both a bioluminescence bioreporter panel and live/dead staining, we observed that membrane damage played a role in the toxicity of MWCNTs. A subsequent viability study using three strains of bacteria-two gram-negative (Escherichia coli, Pseudomonas aeruginosa) and one gram-positive (Bacillus subtilis)-showed significant MWCNT toxicity in hypotonic water and phosphate-buffered saline solution, compared with the MWCNT toxicity towards the same bacteria incubated in isotonic-rich media. Using a field-emission scanning electron microscope, we demonstrated that membrane damage is caused largely by MWCNTs trapping bacteria and piercing the cell walls. As a result of our observations, we propose integrating MWCNTs and bacteria degradation for pollutant removal in nutrient-rich media to minimize the toxicity effect of CNTs.

The scarcity of clean water affecting many parts of the world encourages efforts to improve water reclamation processes, which rely on their capability to remove diverse types of water pollutants and contaminants. Thus this study reports the application of bamboo fiber powders as potential low-cost sorbent for removal of noxious organic compounds in aqueous solution. Bisphenol A, a bio-refractory endocrine disruptor compound, was chosen as model compound in order to easily follow the separation process. Principal component analysis of the FTIR spectra and BET surface area measurements were performed on treated bamboo fiber powders. Treatment of the raw powders with alkali, ionic and non-ionic surfactants appeared to improve the bisphenol A removal performance of the bamboo fiber powders with the best removal efficiency reached at 39 % for a sorbent dosage of 4 g.L -1 gained after a bamboo treatment using the cationic surfactant. Effects of contact time, sorbent dosage and particle sizes (55µm, 300 µm and 1000 µm) of cationic surfactant treated bamboo fiber powders towards removal of bisphenol A were further assessed in a batch system with an optimum removal observed for 55 µm particle size.