Biotechnology Letters

Surplus biological sludge from wastewater treatment operations was converted into activated carbon and then added to the aerated vessel of an activated sludge process treating phenol and glucose. The addition of activated carbon, either sludge-based or commercial, enhanced phenol removal from 58 to 98.7% and from 87 to 93% for COD with feed concentrations of 100 mg phenol l−1 and 2500 mg COD l−1. No differences were found between the activated sludge-activated carbon bench scale continuous reactors operating with either commercial or sludge-based activated carbon in spite of the higher adsorption capacity of the former.

The ability of a biocatalyst to tolerate furan inhibitors present in hemicellulose hydrolysates is important for the production of renewable chemicals. This study shows EMFR9, a furfural-tolerant mutant of ethanologenic E. coli LY180, has also acquired tolerance to 5-hydroxymethyl furfural (5-HMF). The mechanism of action of 5-HMF and furfural appear similar. Furan tolerance results primarily from lower expression of yqhD and dkgA, two furan reductases with a low Km for NADPH. Furan tolerance was also increased by adding plasmids encoding a NADPH/NADH transhydrogenase (pntAB). Together, these results support the hypothesis that the NADPH-dependent reduction of furans by YqhD and DkgA inhibits growth by competing with biosynthesis for this limiting cofactor.

Using soil enrichment techniques we have isolated micro-organisms capable of degrading simple nitrile compounds. One species identified as anAgrobacterium spp. was examined in detail. This isolate was capable of utilising a range of aliphatic and aromatic nitriles as sole sources of carbon and nitrogen. Assays for enzymes involved in nitrile degradation and growth/production studies with this organism growing on acetonitrile indicated that breakdown occurred via a two step mechanism firstly to the amide and then via the production of the corresponding acid with the subsequent release of ammonia. Our studies indicate that the system of nitrile breakdown is inducible and levels of the amidase are 170 times that of the nitrile hydratase in crude extracts.

The activity of freshwater algae in drinking water supply at various ozone contact times was investigated to evaluate ozonation processes used for sterilization of algae. O production rates of algae just after ozonation were severely retarded even by short ozone contact. The algal growth rate was also declined with increase of ozone contact time and completely inhibited by ozonation for 60 min. These results implied that the usual treatment time applied in conventional ozonation processes is not sufficient but at least 60 min of ozonation is required for a complete sterilization of freshwater algae in drinking water source.

The lyophilization of proteins in microplates, to assess and optimise formulations rapidly, has been applied for the first time to a therapeutic protein and, in particular, one that requires a cell-based biological assay, in order to demonstrate the broader usefulness of the approach. Factorial design of experiment methods were combined with lyophilization in microplates to identify optimum formulations that stabilised granulocyte colony-stimulating factor during freeze drying. An initial screen rapidly identified key excipients and potential interactions, which was then followed by a central composite face designed optimisation experiment. Human serum albumin and Tween 20 had significant effects on maintaining protein stability. As previously, the optimum formulation was then freeze-dried in stoppered vials to verify that the microscale data is relevant to pilot scales. However, to validate the approach further, the selected formulation was also assessed for solid-state shelf-life through the use of accelerated stability studies. This approach allows for a high-throughput assessment of excipient options early on in product development, while also reducing costs in terms of time and quantity of materials required.

Using a TaqMan gene probe targeting the 16S rDNA of acidophilic hydrogen-producing bacteria (HPB), the abundance of this HPB in the biomass was found to increase from 0.02 to 72% in a single batch treating rice slurry waste at pH 4.5 over 130 h. The corresponding abundances were 4.4% in the batch operated at pH 5.0 and 0.01–0.02% at pH 5.5–6.5. During the growth phase, the generation time for the acidophilic HPB at pH 4.5 averaged 3.5 h.

This study aimed to examine the metabolising effect of chrysin by investigating the mRNA expression levels of PPARα and its related cellular mechanisms in HCT116 cells. The mRNA expression of PPARα was significantly induced in HCT116 cells following treatment with chrysin for 36 h, but the mRNA expression of PPARα was inhibited, when the cells were treated with a combination of chrysin and MK886 (PPARα inhibitor). This phenomenon proved that the incorporation of MK886 lowers the expression levels of PPARα, thus enabling us to study the function of PPARα. The cell population of the G0/G1 phase significantly increased in chrysin-treated cells, which was accompanied by a decrease in the percentage of S phase cell population after 12 h of treatment. However, treatments of HCT116 cells with chrysin only or a combination of chrysin and MK886 did not show the opposite situation in the G0/G1 and S phase cell populations, indicating that the expression of PPARα may not be associated with the cell cycle in the treated cells. The migration rate in chrysin-treated HCT116 cells was reduced significantly after 24 and 36 h of treatments. However, the activity was revived, when the expression of PPARα was inhibited, indicating that the migration activity of chrysin-treated cells is likely correlated with the expression of PPARα. Comparison of the CYP2S1 and CYP1B1 mRNA expression in chrysin only treated, and a combination of chrysin and MK886-treated HCT116 cells for 24 and 36 h showed a significant difference in the expression levels, indicating that PPARα inhibitor could also modify the expression of CYP2S1 and CYP1B1. The study indicates that PPARα may play an essential role in regulating the migration activity, and the expression of CYP2S1 and CYP1B1 in chrysin-treated colorectal cancer cells.

Candida parapsilosis was grown for 59 h in a medium containing corn cob hydrolysate consisting of 50 g xylose l−1, 3.0 g glucose l−1, 2.0 g arabinose l−1, and 0.9 g acetic acid l−1. A biomass of 9.1 g l−1 was produced with 36 g xylitol l−1 and 2.5 g ethanol l−1. In a medium containing 50 g xylose l−1 instead of corn cob hydrolysate, the concentrations of cells, xylitol, and ethanol were 8.6 g l−1, 33 g l−1, and 0.2 g l−1, respectively. The differences between two cultures were due to the glucose and arabinose in the corn cob hydrolysate stimulating growth and the low concentration of acetic acid stimulating xylitol production.

An aluminium hydroxide adjuvant induced a more elevated and rapid immune responses against short peptides conjugated to the Keyhole Lympet Hemocyanin carrier than immuneasy adjuvant. Furthermore, since carrier proteins may compete with the fused or chemically linked polypeptides in eliciting antigen-specific immune response, we classified the immunogenicity of the most common carrier proteins used in molecular biology for antigen expression and mouse immunisation. The disulfide isomerase protein A gave a carrier with the lowest immunogenicity whilst disulfide isomerase protein C gave the highest immunogenicity and therefore should be avoided as a fusion partner. Using this protein as a model, we identified and located the immunodominant epitopes along its sequence. These results now enable the combination of carrier and immunisation conditions to be optimized.