Development Of An Animal Model To Recover Poly(3-Hydroxybutyrate) Granules From Dried Cells Of Cupriavidus Necator H16

The importance of developing an environmentally friendly and efficient recovery process of polyhydroxyalkanoates (PHAs) from bacterial cells motivated this research. One of the objectives of this study was to evaluate the welfare and tolerability of the animal model, Sprague Dawley given lyophilized cells of Cupriavidus necator H16 as sole diet source. C. necator H16 was cultured using a mineral medium containing crude palm kernel oil (CPKO) as the sole carbon source. The bacterial cells containing about 37 wt% of poly(3-hydroxybutyrate), P(3HB) were used as a source of protein. By taking into account the well-documented nutritive aspects of C. necator cells, the lyophilized cells were given as feed source to animal model (Sprague Dawley). Groups of 6 animals each for both sexes were fed with lyophilized cells of C. necator H16 for study intervals of 7, 14 and 28 days. No mortality was observed and the test animals were found to tolerate well with the whole cell diet. In comparison with the control animals, the test group showed poor weight gain. This is due to the fact that the actual nutritious portion of the feed received by test animals was less than half by weight as compared with the feed consumed by control animals. Haematology and serum biochemistry analyses did not reveal any significant abnormalities

Recovery of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from Ralstonia eutropha cultures with non-halogenated solvents

Reduced downstream costs, together with high purity recovery of polyhydroxyalkanoate (PHA), will accelerate the commercialization of high quality PHA-based products. In this work, a process was designed for effective recovery of the copolymer poly(hydroxybutyrate-co-hydroxyhexanoate) (P(HB-co-HHx)) containing high levels of HHx (>15 mol%) from Ralstonia eutropha biomass using non-halogenated solvents. Several non-halogenated solvents (methyl isobutyl ketone, methyl ethyl ketone, and butyl acetate and ethyl acetate) were found to effectively dissolve the polymer. Isoamyl alcohol was found to be not suitable for extraction of polymer. All PHA extractions were performed from both dry and wet cells at volumes ranging from 2 mL to 3 L using a PHA to solvent ratio of 2% (w/v). Ethyl acetate showed both high recovery levels and high product purities (up to 99%) when using dry cells as starting material. Recovery from wet cells, however, eliminates a biomass drying step during the downstream process, potentially saving time and cost. When wet cells were used, methyl isobutyl ketone (MIBK) was shown to be the most favorable solvent for PHA recovery. Purities of up to 99% and total recovery yields of up to 84% from wet cells were reached. During polymer recovery with either MIBK or butyl acetate, fractionation of the extracted PHA occurred, based on the HHx content of the polymer. PHA with higher HHx content (17–30 mol%) remained completely in solution, while polymer with a lower HHx content (11–16 mol%) formed a gel-like phase. All PHA in solution could be precipitated by addition of threefold volumes of n-hexane or n-heptane to unfiltered PHA solutions. Effective recycling of the solvents in this system is predicted due to the large differences in the boiling points between solvent and precipitant. Our findings show that two non-halogenated solvents are good candidates to replace halogenated solvents like chloroform for recovery of high quality PHA. Biotechnol. Bioeng. 2013; 110: 461–470. © 2012 Wiley Periodicals, Inc.Malaysia-MIT Biotechnology Partnership Programm

Preparation and Characterization of Electrospun Food Biopackaging Films of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Derived From Fruit Pulp Biowaste

In the present study, circular economy based and potentially low-cost poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was produced by mixed microbial cultures derived from fruit pulp, an industrial by-product of the juice industry. Three different chemical routes, namely non-extraction, extraction with sodium hypochlorite (NaClO), and extraction with chloroform, in combination with filtering and centrifugation, were explored to purify the biopolymer and find the most optimal solution for its processing via electrospinning. The resultant ultrathin fiber mats of the different extracted PHBV materials were thermally post-processed at different temperatures in order to obtain continuous films adequate for food packaging applications. The resultant films were characterized in terms of morphology, crystallinity as well as thermal, mechanical, and barrier properties. The results showed that extraction with both chloroform and NaClO with a post-treatment of filtering and centrifugation of the PHBV-containing biomass were necessary refining steps to allow its processing by electrospinning. In particular, the PHBV extracted with chloroform presented the highest degree of purity, resulting in more transparent films with lower wettability and higher flexibility. The here-formulated electrospun films made of biomass derived from biowaste exhibit great potential as interlayers or coatings for food biopackaging applications

Polyethylene/Polyhydroxyalkanoates-based Biocomposites and Bionanocomposites

The development of advanced polymer composite materials having superior mechanical properties has opened up new horizons in the field of science and engineering. Polyethylene (PE) is considered one of the most widely used thermoplastics in the world due to its excellent properties which have excellent chemical inertness, low coefficient of friction, toughness, near-zero moisture absorption, ease of processing and electrical properties. Polyhydroxyalkanoates (PHAs) are garnering increasing attention in the biodegradable polymer market because of their promising properties such as high biodegradability in different environments. This chapter covers polyethylene/polyhydroxyalkanoates-based biocomposites and bionanocomposites. It summarizes many of the recent research accomplishments in the area of PE/PHAs-based biocomposites and bionanocomposites such as state-of-the-art regarding different methods of their preparation. Also discussed are different characterization techniques and use of PE/PHAs-based biocomposites and bionanocomposites in biomedical, packaging, structural, military, coating, fire retardant, aerospace and optical applications, along with recycling and lifetime studies

Effect of Different Curry Flavor Concentrations on the Fermentation Process and Lactic Acid Bacteria of Layang Scad (Decapterus macrosoma)

For various socio-economic and technical factors, fermentation process is among the commonly used method for fish preservation in South-Eastern Asia. However, the fermented fish were not well accepted by some people due to its unpleasant odour and unique taste. In this study, layang scad (Decapretus macrosoma) has been used to study the effect of different curry flavor concentrations on the fermentation process and microflora of lactic acid bacteria. This study was carried out to determine the physical characteristics, microflora of lactic acid bacteria and sensory acceptability of the product. The fish were fermented for 10 days with different concentrations of curry flavor which were at 5%, 7.5%, 10% and control, no addition of curry flavor. The fermented fish were analyzed in terms of pH, firmness, lactic acid concentration and sensory evaluation. Over the fermentation period, pH and firmness values were decreased. Meanwhile, the concentration of lactic acid and colony-forming unit (CFU) of lactic acid bacteria were increased. The effect of fermentation by using different concentrations of curry flavor was observed and no significant different was found on CFU of lactic acid on MRS and M17 agar. Sensory evaluation showed that fermented fish with 10% concentration of curry flavor is the most acceptable by the sensory panelists as it has the highest acceptability score compared to other concentrations. It can be concluded that addition of 10% curry flavor in the formulation of fermented fish is the best in terms of physical characteristic, microbial quality and sensory acceptability

Effect of Different Curry Flavor Concentrations on the Fermentation Process and Lactic Acid Bacteria of Layang Scad (

For various socio-economic and technical factors, fermentation process is among the commonly used method for fish preservation in South-Eastern Asia. However, the fermented fish were not well accepted by some people due to its unpleasant odour and unique taste. In this study, layang scad (Decapretus macrosoma) has been used to study the effect of different curry flavor concentrations on the fermentation process and microflora of lactic acid bacteria. This study was carried out to determine the physical characteristics, microflora of lactic acid bacteria and sensory acceptability of the product. The fish were fermented for 10 days with different concentrations of curry flavor which were at 5%, 7.5%, 10% and control, no addition of curry flavor. The fermented fish were analyzed in terms of pH, firmness, lactic acid concentration and sensory evaluation. Over the fermentation period, pH and firmness values were decreased. Meanwhile, the concentration of lactic acid and colony-forming unit (CFU) of lactic acid bacteria were increased. The effect of fermentation by using different concentrations of curry flavor was observed and no significant different was found on CFU of lactic acid on MRS and M17 agar. Sensory evaluation showed that fermented fish with 10% concentration of curry flavor is the most acceptable by the sensory panelists as it has the highest acceptability score compared to other concentrations. It can be concluded that addition of 10% curry flavor in the formulation of fermented fish is the best in terms of physical characteristic, microbial quality and sensory acceptability

Screening for Direct Production of Lactic Acid from Rice Starch Waste by Geobacillus stearothermophilus

Lactic acid recently became an important chemical where it is widely used in many industries such as food, cosmetic, chemical and pharmaceutical industry. The present study focuses on the screening for lactic acid production from rice starch waste using a thermophilic amylolytic bacterium, Geobacillus stearothermophilus. There is no information available on direct fermentation of lactic acid from rice starch waste using G. stearothermophilus. The effects of different parameters such as temperature, pH, incubation time, agitation speed, concentration of nitrogen and carbon sources on the lactic acid production were assessed. The highest concentration of lactic acid produced was 5.65 ± 0.07 g/L at operating conditions of 60°C, pH 5.5, 48 h, 200 rpm of agitation speed with 5% concentrations of both carbon and nitrogen source. The findings indicated that rice starch waste can be successfully converted to lactic acid by G. stearothermophilus

Screening for Direct Production of Lactic Acid from Rice Starch Waste by Geobacillus stearothermophilus

Lactic acid recently became an important chemical where it is widely used in many industries such as food, cosmetic, chemical and pharmaceutical industry. The present study focuses on the screening for lactic acid production from rice starch waste using a thermophilic amylolytic bacterium, Geobacillus stearothermophilus. There is no information available on direct fermentation of lactic acid from rice starch waste using G. stearothermophilus. The effects of different parameters such as temperature, pH, incubation time, agitation speed, concentration of nitrogen and carbon sources on the lactic acid production were assessed. The highest concentration of lactic acid produced was 5.65 ± 0.07 g/L at operating conditions of 60°C, pH 5.5, 48 h, 200 rpm of agitation speed with 5% concentrations of both carbon and nitrogen source. The findings indicated that rice starch waste can be successfully converted to lactic acid by G. stearothermophilus

Revisiting the Single Cell Protein Application of Cupriavidus necator H16 and Recovering Bioplastic Granules Simultaneously

Cupriavidus necator H16 (formerly known as Hydrogenomonas eutropha) was famous as a potential single cell protein (SCP) in the 1970s. The drawback however was the undesirably efficient accumulation of non-nutritive polyhydroxybutyrate (PHB) storage compound in the cytoplasm of this bacterium. Eventually, competition from soy-based protein resulted in SCP not receiving much attention. Nevertheless, C. necator H16 remained in the limelight as a producer of PHB, which is a material that resembles commodity plastics such as polypropylene. PHB is a 100% biobased and biodegradable polyester. Although tremendous achievements have been attained in the past 3 decades in the efficient production of PHB, this bioplastic is still costly. One of the main problems has been the recovery of PHB from the cell cytoplasm. In this study, we showed for the first time that kilogram quantities of PHB can be easily recovered in the laboratory without the use of any solvents and chemicals, just by using the cells as SCP. In addition, the present study also demonstrated the safety and tolerability of animal model used, Sprague Dawley given lyophilized cells of C. necator H16. The test animals readily produced fecal pellets that were whitish in color, as would be expected of PHB granules. The pellets were determined to contain about 82-97 wt% PHB and possessed molecular mass of around 930 kg/mol. The PHB granules recovered biologically possessed similar molecular mass compared to chloroform extracted PHB [950 kg/mol]. This method now allows the production and purification of substantial quantities of PHB for various experimental trials. The method reported here is easy, does not require expensive instrumentation, scalable and does not involve extensive use of solvents and strong chemicals

Biological recovery and properties of poly(3-hydroxybutyrate) from Cupriavidus necator H16

In the present study, we observed that laboratory rats readily consumed lyophilized cells of Cupriavidus necator H16 cultivated using palm oil containing 39 wt% poly(3-hydroxybutyrate) [P(3HB)] as sole diet source. The test animals excreted whitish fecal pellets containing 82–97 wt% P(3HB). The remaining impurities could be easily removed by washing the pellets with water and/or low concentrations of detergent, which resulted in P(3HB) granules of a high purity. The molecular masses and thermal properties of P(3HB) obtained by this method were almost similar to P(3HB) extracted from bacterial cells using chloroform. The method reported here is simple and eliminates the need for solvents and strong chemicals, thus resulting in P(3HB) production that is more ecofriendly