Screening for a low-cost Haematococcus pluvialis medium reveals an unexpected impact of a low N:P ratio on vegetative growth

Haematococcus pluvialis is the current better source of natural astaxanthin, a high-value carotenoid. Traditionally, the production process of astaxanthin by this algae is achieved by a two-stage system: during the first stage, vegetative “green” cells are produced and then converted, in the second stage, into cysts that accumulate astaxanthin. In this work, a medium screening strategy based on the mixing of a 3-component hydroponic fertilizer was applied to identify a new formulation optimized for the vegetative stage. A maximal and high cell density of 2 x 106 cells mL−1 was obtained in a medium containing a high level of phosphate relative to nitrate, resulting in a N:P ratio much lower than commonly used media for H. pluvialis. In this medium, cells remained at the vegetative and motile stage during a prolonged period of time. Both high cell density culture and motile stage persistence was proved to be related to the N:P feature of this medium. We conclude that the macrozoid stage of H. pluvialis is favored under high-P and low-N supply and that low-cost hydroponic fertilizers can be successfully used for achieving high density cultures of vegetative cells of H. pluvialis.BIOVAMA

Effect of carbon nanofibre structure on the binding of antibodies

Potential biomedical applications for carbon nanofibres include, but are not limited to, biosensors and drug delivery vehicles. For such applications, it is essential to know how carbon nanotubes interact with antibodies and proteins. We report on the successful adsorption of monoclonal CD3 antibodies on two types of carbon nanofibre produced by the same method and having the same average size and shape, but differing in surface structure and chemistry due to dissimilar post-treatments. Binding of proteins to nanofibres is enhanced by poly (L-lysine) (PLL) and improves with increasing disorder and hydrophilicity of the nanofibres' surface. Oxidized and disordered surfaces of pyrolytically stripped nanofibres show improved wetting and attachment of PLL and proteins compared to hydrophobic and well-ordered surfaces of heat-treated nanofibres. These results show that the surface of carbon nanofibres can be tailored for their use in biomedical applications

Effect of carbon nanofibre structure on the binding of antibodies

Potential biomedical applications for carbon nanofibres include, but are not limited to, biosensors and drug delivery vehicles. For such applications, it is essential to know how carbon nanotubes interact with antibodies and proteins. We report on the successful adsorption of monoclonal CD3 antibodies on two types of carbon nanofibre produced by the same method and having the same average size and shape, but differing in surface structure and chemistry due to dissimilar post-treatments. Binding of proteins to nanofibres is enhanced by poly (L-lysine) (PLL) and improves with increasing disorder and hydrophilicity of the nanofibres' surface. Oxidized and disordered surfaces of pyrolytically stripped nanofibres show improved wetting and attachment of PLL and proteins compared to hydrophobic and well-ordered surfaces of heat-treated nanofibres. These results show that the surface of carbon nanofibres can be tailored for their use in biomedical applications