Biosynthesis of Bacterial Cellulose by Extended Cultivation with Multiple Removal of BC Pellicles

Extended cultivation with multiple removal of BC pellicles is proposed herein as a new biosynthetic process for bacterial cellulose (BC). This method enhances the BC surface area by 5–11 times per unit volume of the growth medium, improving the economic efficiency of biosynthesis. The resultant BC gel-films were thin, transparent, and congruent. The degree of polymerization (DP) and elastic modulus (EM) depended on the number of BC pellicle removals, vessel shape, and volume. The quality of BC from removals II–III to VII was better than from removal I. The process scale-up of 1:40 by volume increased DP by 1.5 times and EM by 5 times. A fact was established that the symbiotic Medusomyces gisevii Sa-12 was adaptable to exhausted growth medium: the medium was able to biosynthesize BC for 60 days, while glucose ran low at 24 days. On extended cultivation, DP and EM were found to decline by 39–64% and 57–65%, respectively. The BC gel-films obtained upon removals I–VI were successfully trialed in experimental tension-free hernioplasty.

Improving biological production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) co-polymer: a critical review

Although poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is the most promising biopolymer for petroleum-based plastics replacement, the low processes productivity as well as the high sale price represent a major barrier for its widespread usage. The present work examines comparatively the existing methods to enhance the yield of the PHBV co-polymer biologically produced and/or reduce their costs. The study is addressed to researchers working on the development of new biological production methods and/or the improvement of those currently used. At this aim, the authors have considered the analysis of some crucial aspects related to substrates and microorganism’s choice. The production strategies have been individuated, presented and discussed, either based on a single aspect (type of substrate or microorganism) or based on combined aspects (type of substrate and microorganism). Process operating conditions have been discussed as well. The analysis indicates that the addition of 3HV precursors is capable to dramatically enhance the hydroxyvalerate fraction in the produced biopolymers. On the other hand, due to the high costs of the 3HV precursors, the utilization of wild bacterial species capable to produce the hydroxyvalerate fraction from unrelated carbon sources (i.e. no 3HV precursors) also can be considered a valuable strategy for costs reduction. Moreover, metabolic engineering techniques can be successfully used to promote 3HV precursors-independent biosynthesis pathways and enhance the process productivity. The use of mixed cultures or extremophile bacteria avoids the need of sterile working conditions, and therefore favours the process scale-up. The utilization of the organic waste as substrate plays a key role for a sharp reduction of production costs. Finally, the selection of the most suitable substrate-microorganism combination cannot be separated by the adoption of an appropriate choice of reactor configuration and abiotic factors. Graphic abstract

Environmental aspects and economic evaluation of new green hydrolysis method for waste feather processing

In recent years, an increase in the chicken meat process industry has been growing quickly, which brings a large amount of difficult to process waste, chicken feathers. These billions of kilograms create a serious waste problem over the world, furthermore, poultry feather processing is not only particularly difficult but also relatively expensive. In fact, there is no technology suitable for processing such huge quantities of feathers to guarantee sustainable development of the chicken meat industry together with processing of waste feathers. This article introduces a newly designed and original, highly efficient and environmentally friendly method of physicochemical hydrolysis of waste feathers. The hydrolysis is carried out in the presence of a weak organic carboxylic acid; thus, the resulting hydrolysate does not contain any salts or ashes. Therefore, a resulting hydrolysate, which includes a mixture of amino acids, peptides, proteins, glycoproteins and free fatty acids, is suitable for a variety of applications; e.g. as a chondroprotective agent in the treatment of joint diseases, nutrients for crop plants or targeted biostimulants for agriculture. This paper is focused not only on the process scale-up but also on environmental aspects and economic evaluations to bring general view of the process. Graphic abstract

Catalyst Heating Characteristics in the Traveling-Wave Microwave Reactor

Traveling-Wave Microwave Reactor (TMR) presents a novel heterogeneous catalytic reactor concept based on a coaxial waveguide structure. In the current paper, both modeling and experimental studies of catalyst heating in the TMR are presented. The developed 3D multiphysics model was validated from the electromagnetic and heat transfer points of view. Extrudes of silicon carbide (SiC) were selected as catalyst supports and microwave absorbing media in a packed-bed configuration. The packed-bed temperature evolution was in good agreement with experimental data, with an average deviation of less than 10%. Both experimental and simulation results show that the homogeneous temperature distribution is possible in the TMR system. It is envisioned that the TMR concept may facilitate process scale-up while providing temperature homogeneity beyond the intrinsic restrictions of microwave cavity systems.

Environmental Aspects and Economic Evaluation of New Green Hydrolysis Method For Waste Feather Processing

In recent years, an increase in the chicken meat process industry has been growing quickly, which brings a large amount of difficult to process waste, chicken feathers. These billions of kilograms create a serious waste problem over the world, furthermore, poultry feather processing is not only particularly difficult but also relatively expensive. In fact, there is no technology suitable for processing such huge quantities of feathers to guarantee sustainable development of the chicken meat industry together with processing of waste feathers. This article introduces a newly designed and original, highly efficient and environmentally friendly method of physicochemical hydrolysis of waste feathers. The hydrolysis is carried out in the presence of a weak organic carboxylic acid; thus, the resulting hydrolysate does not contain any salts or ashes. Therefore, a resulting hydrolysate, which includes a mixture of amino acids, peptides, proteins, glycoproteins and free fatty acids, is suitable for a variety of applications; e.g. as a chondroprotective agent in the treatment of joint diseases, nutrients for crop plants or targeted biostimulants for agriculture. This paper is focused not only on the process scale-up but also on environmental aspects and economic evaluations to bring general view of the process.