Agro-Industrial Waste Materials as Substrates for the Production of Poly(3-Hydroxybutyric Acid)

Accumulation of recalcitrant plastics in the environment has become a world-wide problem in today’s societies. Rapid depletion of natural resources for synthetic plastics along with environmental concerns has directed research towards finding alternatives to petroleum-based polymers. Poly(3-hydroxybutyric acid) P(3HB), as one of these alternatives, have attracted much attention in recent years due to their varied mechanical properties, biocompatibility and iodegradability. The aim of this study was to identify an agro-industrial waste resource economically suitable for large-scale production of P(3HB), to optimize the production using Response Surface Methodology in small-scale and subsequently, to test the production in a continuously stirred tank reactor. Among a range of agro-industrial waste, orange peel was selected as the most suitable for P(3HB) production. P(3HB) concentration of 1.24 g P(3HB)/L culture broth with 41% P(3HB)/dcw yield was obtained using orange peel as the sole carbon source in optimized medium with a modified strain of Bacillus subtilis (B. subtilis OK2)

Dual biopolymer production and separation from cultures of Bacillus spp.

In the search of alternative new materials for biodegradable plastics, biopolymers provide attractive solutions with their vast range of applications. A challenge in industrial production of biopolymers is their high cost, and one approach to minimise the cost is expanding the number of valuable products obtained from a single batch. The aim of this thesis was the dual production of biopolymers, P(3HB) and γ-PGA from cheap substrates with the view to lay grounds for a feasible, innovative, low cost production process. A common denominator between the two biopolymers focused in this thesis, (P(3HB) and γ-PGA), was that they both could be produced by Bacillus sp. One out of five strains screened, Bacillus subtilis OK2, was selected and the structures of both biopolymers produced were confirmed. Subsequently, optimisation of the production medium via statistical optimisation tools, and scaling-up of the process from shaken flasks to fermenters were carried out. Statistical design tool Placket Burman (PB), (Design Expert 6.0), was used to determine the effect of medium components on γ-PGA and P(3HB) production and to identify the crucial medium components in production media. The outcome of PB analysis of dual polymer production did not match the PB analysis of single polymer production. Considering the complexity of the dual polymer production mechanism, central composite design was applied after the number of parameters was reduced from five to three. A medium composed of 20 g/L glucose, 1.5 g/L yeast extract, 2.4 g/L citric acid, 32 g/L glutamic acid and 12 g/L ammonium sulphate was identified as the dual polymer production medium. Using an inoculum medium different from the production medium proved to have a positive effect on the production. Consequently, 1 g/L P(3HB) and 0.4 g/L γ-PGA in shaken flasks and 0.6 g/L P(3HB) and 0.2 g/L γ-PGA in single batch fermenters were produced with the strain Bacillus subtilis OK2. Selection of biowaste for the dual production was conducted using four biowastes; rapeseed cake, wheat bran, Spirulina powder and orange peel; using four pre-treatment methods, acid treatment, alkaline treatment, water infusion, and microwave exposure. γ-PGA production could not be detected when any of the waste materials was used as a sole medium component. Orange peel using water infusion pre-treatment was found to be the most suitable biowaste for the production of P(3HB). Bioreactor experiments showed that 1.24 g/L P(3HB) could be produced using orange peel as carbon source supplemented with yeast extract and citric acid. Dual polymer production using orange peel as carbon source proved to be more challenging as some of the ingredients in orange peel interfered with the dual production and inhibited production of both polymers. Although the different sugars in orange peel had a positive effect on production, pH control coupled with DOT control proved to be essential to overcome inhibition and 0.2 g/L of each polymer were produced in 79 h. For the separation of the two polymers from the culture broth, magnetic field, floatation, and sedimentation methods were investigated. Exposure to magnetic field was found to be inhibitory for P(3HB) production. The use of floatation and sedimentation for the online separation of cells with and without polymer to facilitate a recycle strategy exhibited negative results. This was found to be due to cells undergoing cell lyses at the early stages of the fermentation releasing P(3HB) granules into the fermentation medium. The size distribution of these granules was identified. The results elicit the possibility of using cell auto-lysis behaviour for the separation of the two polymers from the culture broth leading to a reduction of costs

A Strategy for Dual Biopolymer Production of P(3HB) and γ-PGA

BACKGROUND Production of biopolymers has gained considerable attention because of their biodegradability, biocompatibility, and as suitable replacements for mineral-based polymers. Despite advances in production process, a notable drawback still exists due to high production cost. The aim of this paper is to provide a production strategy for cost reduction. The suggested process may be adopted to other polymers, useable to wide audience in biopolymer research. RESULTS Dual production of two commercially important biopolymers, P(3HB) and γ-PGA, in a single batch from cheap substrates was studied, as proof of concept, for a feasible low cost dual biopolymer production. The dual production from a single batch yielded 1 g/L P(3HB) and 0.4 g/L γ-PGA using Bacillus subtilis OK2 (B. subtilis OK2). When orange peel was substituted as a cheap carbon source for dual production, coupled pH and dissolved oxygen control proved to be essential to overcome the inhibition imposed by the non-sugar components of the substrate. The cell lysis and release of P(3HB) granules in the dual production medium can be exploited of as a new approach for separation of this polymer. CONCLUSION This proof of concept study provides a new approach from upstream to downstream processing for low cost production of dual biopolymers

Estimation of wavelet threshold value for surface EMG baseline removal

High quality of surface electromyography is vital during investigation on muscle activity. Low quality of surface EMG signals causes extracted signals to be inaccurate and lead to misinterpretation and misclassification of the signals. A surface EMG signal quality is determined by the ratio of muscle contraction to its baseline during muscle relaxation period. Baseline noises are originated from powerline, cable motion artefact, electronics of the amplification systems and skin-electrode interface. The noises are quite difficult to be removed by digital or active filter since they do not have specific frequency range like powerline interference and corner frequency noise. However, wavelet de-noising enables users to remove noise by accessing both frequency and time information. Baseline surface EMG noise is possible to be removed by estimating de-noise threshold based on mean absolute value and root mean square of its baseline. The result of this study shows that the proposed estimation of threshold method is better than the conventional threshold setting

Treatment and reutilization of effluents: one Mediterranean project

The problematic of effluent treatment from olive oil industry as been the subject of an European Commission funded project (INCO-MED programme): “Mediterranean Usage of Biotechnological Treated effluent Water”. The potential that effluent offers to increase the availability of water, in mediterranean regions, was the final goal of the project, co-ordinated by INETI with partners from EU and MPC. In the project different systems for the treatment of this effluent had been studied: reactors systems (Intensive type) based on the jet-loop principle (JACTO) and an anaerobic UASB hybrid type reactor technology; lagoons (extensive type) for municipal wastewater treatment were also applied. The aerobic JACTO system demonstrated high unit capacity for biological conversion and operation at different loadings, allowing the removal of the pollutant organic load and the toxicity associated with this effluent. The use of this type of reactor for pre-treatment of OOWW prior to disposal on a lagoon system was tested at FSS (Morocco). Use of fungi as a pre-treatment was tested by UNITUS (Italy), EBC (Turkey) and CBS (Tunisia). In this way the effluent could be “improved” as demonstrated in the case of anaerobic digestion and biogas production (CBS). Effluent improvement and enrichment with phosphate was also tested by UNITUS. Analytical monitoring methodologies were developed at IA (Spain) and treated effluents were tested for a number of agricultural applications in different countries. The different alternatives studied will be analysed and compared taking account of technological and socio-economical criteria in relation with the project objectives

Primary Hyperparathyroidism Patients with Positive Preoperative Sestamibi Scan and Negative Ultrasound Are More Likely to Have Posteriorly Located Upper Gland Adenomas (PLUGs)

BackgroundStandard preoperative imaging for primary hyperparathyroidism usually includes sestamibi scanning (MIBI) and ultrasound (US). In a subset of patients with a positive MIBI and a negative US, we hypothesize that the parathyroid adenomas are more likely to be located posteriorly in the neck, where anatomically they are more difficult to detect by US.MethodsWe retrospectively reviewed the records of 661 patients treated for primary hyperparathyroidism between 2004 and 2009 at a tertiary referral center. We included patients who for their first operation had a MIBI that localized a single lesion in the neck and an US that found no parathyroid adenoma. We excluded patients with persistent or recurrent hyperparathyroidism, and patients with MIBIs that were negative, that had more than one positive focus, or that had foci outside of the neck. Sixty-six cases were included in the final analysis.ResultsA total of 54 patients (83%) had a single adenoma, 4 (6%) had double adenomas, and 7 (11%) had hyperplasia. Thirty-three patients (51%) had a single upper gland adenoma; 19 of these (58%) were posteriorly located upper gland adenomas (PLUGs). PLUGs occurred more often on the right side than on the left (P = 0.048, Fisher's test). PLUGs were also larger than other single adenomas (mean 1.85 vs. 1.48 cm, P = 0.021, t-test). Seventy-six percent of patients successfully underwent a unilateral or focused exploration. Six patients (9%) had persistent disease, which is double our group's overall average (4-5%).ConclusionsPrimary hyperparathyroid patients with preoperative positive MIBI and negative US are more likely to have PLUGs

Dual production of biopolymers from bacteria

Rapid depletion of natural resources with continued demands of an increasing population and high consumption rates of today's world will cause serious problems in the future. This, along with environmental concerns, has directed research towards finding alternatives in variety of sectors including sustainable and environmentally friendly consumer goods. Biopolymers of bacterial origin, with their vast range of applications, biodegradability and eco-friendly manufacturing processes, are one of the alternatives for a more sustainable future. However, the cost of their production is a drawback. Simultaneous production processes have always been an option for researchers in order to reduce cost, but the variable requirements of microorganisms to produce both different and valuable products are a hindering factor. This review will look at some examples and identify ideas towards developing a successful strategy for simultaneous production of bio-products

Foaming and Enzyme-Activity In Fungal Cultures Grown on Sugar-Beet Rosette

WOS: A1985ALT410001