International Conference and Exhibition on Biopolymers and Bioplastics August 10-12, 2015 San Francisco, USA

Cornelia Haas studied molecular biology and biological chemistry at the University of Vienna, Columbia University in the City of New York and the Dublin Institute of Technology. Currently she is doing her PhD project on the production of PHB from alternative feedstocks at the University of Natural Resources and Life Sciences Vienna. She has (co-)authored several papers and presented her work at the Renewable Resources and Biorefinery Conference in Spain (2014).

We developed a cell-recycle membrane bioreactor for the high-cell-density production of poly(3-hydroxybutyrate) (PHB). This fermentation strategy is feasible for low carbon concentrations in the feed stream, as often found in agricultural residues. Cupriavidus necator DSM 545 was continuously supplied with medium containing 50 g/L of glucose. A constant working volume inside the bioreactor was maintained by an external polysulfone microfiltration membrane module. The PHB-production phase was started after 8 hours by supplying nitrogen-free medium. After another 32 hours, 52 g/L dry biomass were accumulated containing 92% PHB, resulting in a high productivity of 1.2 g PHB/Lh.

Cellulose is the most abundant macromolecular on earth observed in large quantity from nature which is predominantly generated by vascular plant and algae, but also by bacteria. Bacterial cellulose (BCel) exhibits the unique physical properties at nanoscale network (i.e. high water content and high tensile strength), and does not require extra processing steps to remove impurities such as lignin, pectin, and hemicellulose. Previous study demonstrated that BCel can be produced semi-continuously utilizing PCS rotating disk bioreactor (PCS-RDB). In this study, different additives including avicel, carboxymeylcellulose, agar and sodium alginate were added into culture medium in PCS-RDB to improve the productivity of BCel and its material property. The produced BCel was analyzed using fourier transform infrared spectroscopy (FTIR), scan electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and dynamic mechanical analysis (DMA). The results demonstrated that both CMC and avicel addition can increase the productivity of BCel in PCS-RDB. The highest BCel production reached 0.64 g/slice when 0.8% of avicel was added. The FTIR and XRD results indicated that CMC and avicel might be incorporated into BCel during production, and disordered BCel structure to decrease its crystallinity. The SEM result showed that the incorporated additives may attach on BCel fibers and increase fiber size. In future work, dynamic mechanical analysis (DMA) should be finish to confirm the effects of different additives addition in mechanical property.

The North Pacific Ocean, the garbage patch, is one area that is affected by this massive and disproportional waste of plastics. Synthetic materials are used by every person in all societies and it is an important source of toxic compounds, such as PCBs, PAHs, and organochlorine pesticides that most of them are endocrine disrupting. Large amounts of plastic debris has been documented on the Pacific Gyre as causing damage to sea organisms by entanglement and ingestion. However, the data related with the quantification of persistent organic pollutants is not available as the physical analysis of this debris. The main outcomes of this research is the results of persistent organic pollutant concentrations from plastic debris 2005, 2007, and from 2014 samples. In 2007, the analysis of seawater surface showed that contained microscopic and nanoplastics particles. In 2014 the information added was microscopic plastics dispersed into seawater at 10 m of depth. The main kind of synthetic plastic found on the sea surface are PE and PP.

Prof. Dr. Paulo José do Amaral Sobral has completed his PhD in 1992 at ENSIC-INPL, France. Now, he is Full Professor at University of São Paulo (USP), campus of Pirassununga (SP), Brazil, where he is the Dean of the Faculty of Animal Science and Food Engineering (FZEA-USP). He has more than 15 years of experience on biopolymers-based films technology, having published more than 130 papers in reputed journals (ISI h index= 25) and serving as an editorial board member in some Journals, such as the Food Engineering Review. He is Associate Editor of the International Journal of Food Studies.

Films based on biopolymers have attracted interest of researchers because they are biodegradable. But, these materials have technological limitations principally due to the hygroscopic characteristic of biopolymers and plasticizers, usually, polyols. An alternative to improve the properties of these materials are the use of nanoparticles as loading. Although montmorillonite is the nanoparticle most used to produce biopolymers based nanocomposite films, laponite has an enormous potential because it is easily dispersed in water, outstanding solvent in the biopolymer film technology. Thus, this work presents results of some physical properties of recently developed nanocomposite films (NF) based on gelatin with different laponite concentrations. NF were prepared with casting film-forming solutions containing 0.0, 1.5, 3.0, 4.5 and 6.0g laponite/100g gelatin on an adequate support and dried on controlled conditions. Glycerol was used as plasticizer. The NFs were characterized for gloss (60°), color (CIELab), thermal (TGA) and mechanical (tensile tests) properties. Moreover, NFs were analyzed by scanning electron microscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). NFs were transparent and homogeneous. NF gloss, color and surface micrographs were not altered by the laponite concentration. And, laponite improved the thermal stability and mechanical properties (increasing Young modulus and tensile strength) of the gelatin-laponite nanocomposites. These results indicated that laponite was well dispersed in the biopolymer matrix. FTIR and XRD spectra corroborated with this statement. These nanocomposites have a great potential to be used in the packaging industry.

Marcos Vinicius Lorevice has completed his B.Sc in Chemistry in 2012 at São Paulo State University (USP) and his M.Sc in 2015 at Federal University of São Carlos, both in Brazil. He is enrolled with his Ph.D studies in Chemistry since 2015 in Federal University of São Carlos, and his research project is being developed in Embrapa Instrumentação, a Brazilian federal research organization He has published four papers in reputed journals and more than eight papers in workshops and scientific meetings.

The increasing discard of petroleum-based packaging has intensified the environmental impacts. An alternative has been the production of biodegradable packaging from low-cost and renewable polymers. Pectin, a naturally occurring polysaccharide, is widely used to make films but presents unfavorable physical properties compared to synthetic polymers. The addition of nanoparticles was reported to improve the mechanical properties of polysaccharide films. The aim of this study was to add chitosan nanoparticles (CSNPs) on pectin (high or low methoxyl degrees) matrices producing nanocomposites: HDM pectin/CSNPs and LDM pectin/CSNPs films; as well as to evaluate the effect of the nanostructure on mechanical properties. CSNPs were synthetized by ionotropic gelatinization and characterized as to zeta potential, average diameter, and FT-IR. The nanocomposite films were obtained by casting from colloidal solution of CSNP/pectin and analyzed by thickness, appearance, FT-IR, and mechanical properties. The CSNPs presented average diameter near to 110 nm and zeta potential near to 50mV. FT-IR showed the interactions between CS and TPP, representing CSNP formation. By the addition of CSNPs into pectin matrices, nanocomposites were successfully formed, showing good visual appearance. CSNPs improved the mechanical properties, with the tensile strength having the most significant enhancement from 30.81 ± 1.50 MPa to 46.95 ± 0.36 MPa for HDM pectin/CSNP and from 26.07 ± 3.78 MPa to 58.51 ± 11.08 MPa for LDM pectin/CSNP. These results show that nanocomposites produced with pectin/CSNPs have improved mechanical properties compared with control pectin films, allowing these novel materials to stand out as an alternative to food packaging production.

Warren Blunt is currently working on a Ph.D. Degree in the Department of Biosystems Engineering at the University of Manitoba.

Medium chain-length polyhydroxyalkanoates (mcl-PHAs) show promise as a renewable alternative to petroleum-derived plastics. One of the requirements for mcl-PHA production to be economically feasible is achieving high productivity in large-scale bioreactors. This may be accomplished through a combination of bioreactor design and implementation of effective control strategies. As is the case in most aerobic bioprocesses, delivery of oxygen is a crucial challenge often limiting the mcl-PHA productivity in many studies. Surprisingly, the effect of oxygen limitation is not well understood in mcl-PHA synthesizing organisms. Oxygen limitation has been described as something to be avoided due to the detrimental effect on growth rate and cell density, but often the effect on cellular mcl-PHA content is not considered. In batch experiments using Pseudomonas putida LS46 grown on 20 mM octanoic acid under nitrogen-excess conditions, oxygen limitation was found to be an effective trigger for mcl-PHA accumulation. A series of experiments were conducted in which dissolved oxygen (DO) was maintained at 40%, 10%, 1%, and 0% (expressed as a percentage of air saturation). Maintenance of DO was achieved by: 1) continual air sparging at a rate of 2 vvm in all experiments; and 2) regulating mixing (250-900 rpm) in experiments in which DO was required to be above 0%. Experiments in which DO was maintained above 0% showed no significant accumulation of mcl-PHA (15.7 ± 4.3% of dry cell weight). However, when the DO was not maintained via the mixing cascade, DO fell to 0% despite air sparging and the cellular mcl-PHA content increased to 48 ± 1.3% DCW. By further increasing the available carbon while maintaining nitrogen in excess, up to 71% cellular mcl-PHA accumulation was observed under oxygen limitation. At 0% DO, some increase in residual cell mass was observed, although the growth rate was significantly slowed (μ = 0.14 h-1 as compared to μmax = 0.69 h-1). These results suggest that manipulation of dissolved oxygen may be an effective way to enhance cellular mcl-PHA content and improve productivity in large-scale continuous or semi-continuous bioreactors.