Bioplastic Production from Eucheuma Cottoni

Plastic waste has become a global problem because it causes environmental pollution. This is because plastic waste is difficult to decompose. There have been numerous solutions proposed, one of which is theuse of bioplastics. In this research, the bioplastics were made from third- generation biomass, namely the eucheuma cottoni. Eucheuma cottoni is contains biopolymer carrageenan, a carbohydrate with unit structures consisting of d-galactose and 3,6 anhydrogalactose with glycosidic bonds. Goal this research is study the effects of sorbitol plasticizer content and bioplastics manufacturing temperature on bioplastics, tensile strength, elongation, and biodegradation rate. The bioplastics were made by extracting 10 grams of eucheuma cottoni powder in 200 ml of distilled water. The algae extract was added with sorbitol (plasticizer) and heated at various temperatures from 45°C until 60°C. The mixture was poured into a mold tin and dried in the oven to a constant weight. The resulting bioplastics were then characterized to determine the tensile strength and biodegradation rate. The results showed that increasing the plasticizer content from 3.5% reduced the tensile strength, however, it increased the elongation and biodegradation rate. The optimal plasticizer content was 4% with a tensile strength value of 4.8309 Mpa, elongation of 24.1548%, and biodegradation rate of 26.9392%. The temperature variable showed that increasing the temperature of making bioplastics could reduce tensile strength, increase elongation and biodegradation rate of bioplastics. The optimum temperature for making bioplastics at 45oC obtained a tensile strength of6.28 Mpa and an elongation of 20.67%. The biodegradation rate was 39.6665%, and the best sorbitol content was received at 4%.

Effects of Adding Laccase to Bacterial Consortia Degrading Heavy Oil

High-efficiency bioremediation technology for heavy oil pollution has been a popular research topic in recent years. Laccase is very promising for the remediation of heavy oil pollution because it can not only convert bio-refractory hydrocarbons into less toxic or completely harmless compounds, but also accelerate the biodegradation efficiency of heavy oil. However, there are few reports on the use of laccase to enhance the biodegradation of heavy oil. In this study, we investigated the effect of laccase on the bacterial consortia degradation of heavy oil. The degradation efficiencies of bacterial consortia and the laccase-bacterial consortia were 60.6 ± 0.1% and 68.2 ± 0.6%, respectively, and the corresponding heavy oil degradation rate constants were 0.112 day−1 and 0.198 day−1, respectively. The addition of laccase increased the heavy oil biodegradation efficiency (p < 0.05) and biodegradation rate of the bacterial consortia. Moreover, gas chromatography–mass spectrometry analysis showed that the biodegradation efficiencies of the laccase-bacterial consortia for saturated hydrocarbons and aromatic hydrocarbons were 82.5 ± 0.7% and 76.2 ± 0.9%, respectively, which were 16.0 ± 0.3% and 13.0 ± 1.8% higher than those of the bacterial consortia, respectively. In addition, the degradation rate constants of the laccase-bacterial consortia for saturated hydrocarbons and aromatic hydrocarbons were 0.267 day−1 and 0.226 day−1, respectively, which were 1.07 and 1.15 times higher than those of the bacterial consortia, respectively. The degradation of C15 to C35 n-alkanes and 2 to 5-ring polycyclic aromatic hydrocarbons by laccase-bacterial consortia was higher than individual bacterial consortia. It is further seen that the addition of laccase significantly improved the biodegradation of long-chain n-alkanes of C22–C35 (p < 0.05). Overall, this study shows that the combination of laccase and bacterial consortia is an effective remediation technology for heavy oil pollution. Adding laccase can significantly improve the heavy oil biodegradation efficiency and biodegradation rate of the bacterial consortia.

Influence of nano-activated carbon on biodegradation of bamboo paper in the soil

Paper made from natural fiber of ampel bamboo (Bambusa vulgaris) and nano-activated carbon from sawdust had been tested as food packaging and showed its ability to maintain freshness and nutritive value of foodstuffs. However, as a packaging material, natural degradability of this alternative natural-fiber paper is required to be tested. This study aims to determine the effect of nano-activated carbon on paper’s biodegradation properties. The results showed that paper treated with nano-activated carbon degraded faster in the soil compared to paper made of bamboo fiber only (control) after 8 weeks of observation. The microorganism population density analysis showed that the paper with nano-activated carbon had a lower microorganism density than the control which accompanied by a decrease in paper weight after 12 weeks of observation. This finding demonstrates the potential utilization of nano-activated carbon as an additive to be inserted into paper to accelerate the biodegradation rate of paper in the soil. The ability of paper to be degraded naturally is very important to support environmental sustainability.

Biodegradable polysarcosine with inserted alanine residues: Synthesis and enzymolysis

Polysarcosine (PSar), a water-soluble polypeptoid, is gifted with biodegradability via random ring-opening copolymerization of sarcosine- and alanine-N-thiocarboxyanhydrides catalyzed by acetic acid in controlled manners. Kinetic investigation reveals the copolymerization behavior of the two monomers. The random copolymers, named PAS, with high molecular weights between 22.0 and 43.6 kg/mol and tunable Ala molar fractions varying from 6% to 43% are able to be degraded by porcine pancreatic elastase within 50 days in mild conditions (pH=8.0 at 37 °C). Both the biodegradation rate and water solubility of PAS depend on the content of Ala residues. PAS with Ala fractions below 43% are soluble in water while the one with 43% Ala self-assembles in water into nanoparticles. Moreover, PAS are non-cytotoxic at the concentration of 5 mg/mL. The biodegradability and biocompatibility endow the Ala-containing PSar with potential to replace PEG as protective shield in drug-delivery.

Effect of Aerating Duration on Hydrocarbon Biodegradation in a Simulated Crude-Oil Polluted Aquatic Environment Undergoing Bioremediation

The aim of this research work was to determine the aerating duration that would be effective in enhancing hydrocarbon biodegradation rate during bioremediation of crude-oil polluted river. Sediment and river-water were placed in four glass troughs labeled CT (control), A, B, and C. The setups were polluted with crude-oil, and allowed undisturbed for 2 weeks. Subsequently, accessible crude-oil on the surface was removed; bacteria and nutrients were then added. Air was bubbled for 3 hours into setups A, B, and C, at daily, 3 days, and 7 days interval respectively. Aeration was not applied to setup CT. On day 1, 7, 14, and 21, hydrocarbon concentration was determined; populations of total heterotrophic bacteria (THB) and hydrocarbon-utilizing bacteria (HUB) were also determined. The time it will take for hydrocarbons in the setups to biodegraded “completely” was calculated using first-order reaction equation. The results obtained showed that 71.43, 86.39, 83.17, and 15.42 % hydrocarbon degradation were obtained in setup A, B, C, and CT respectively. The time it will take for hydrocarbons in the setups to biodegrade “completely” were 129, 89, 101, and 1079 days for A, B, C, and CT respectively. There was slight reduction in population of HUB in setup CT, fairly stable population in setup A, and increase in population of HUB in setups B and C. It is concluded that aerating crude-oil polluted aquatic environment for 3 hours at 3 days interval will be more effective in enhancing hydrocarbon biodegradation rate during bioremediation.

The effect of chemical composition on the biodegradation rate and physical and mechanical properties of polymer composites with lignocellulose fillers

The results of TPLC scientific research, practical experience of their preparation, and application as of 2016 are presented in eight volumes of the “Handbook of Composites from Renewable Materials” (2017, John Wiley & Sons, Inc.). This article provides an analysis of books and articles with open access to the Science Direct (Elsevier) database for the period 2017–2020 to assess the biodegradation rate and physical and mechanical properties of polymer composites with lignocellulosic fillers. The production and use of polymer composites with a thermoplastic polymer matrix and lignocellulosic fillers (TPLC) have significant ecological and eco- nomic prospects since waste biomass from forests, agriculture, and polymers obtained from petroleum raw materials can be used for their production. However, depending on the TPLC application area, there are opposite requirements for the biodegradation rate. For the use in construction and medicine materials and products must have a minimum biodegradation rate. Materials and products for single-use packaging must have the necessary biodegradability potential and have an adjusted biodegradation rate in soil, water, compost environment. Research results show that the properties of TPLC can be significantly influenced not only by the physical but also by the chemical structure of all components of these composites. The chemical properties of polymers, fillers, additives for various purposes can affect their industrial production efficiency.

Biodegradation of Naphthalene Using Glass Beads Roller Bioreactor: Application of Artificial Neural Network Modeling

A roller bioreactor containing inert glass beads was employed to enhance naphthalene biodegradation in an aqueous solution. Mixed culture of microorganisms was isolated from sewage waste sludge and adopted for naphthalene biodegradation. The biodegradation of 300mg/L naphthalene in the bioreactor with no glass beads proceeded slowly until depletion after seven days. In the presence of glass beads, the biodegradation rate was faster; it depleted after four days. The biodegradation rate of naphthalene was equal to 1.99 mgL-1 hr-1 for bioreactor with no beads, while it is equal to 5.42, and 5.54 mgL-1 hr-1 for bioreactor with 40%load, 6mm size and 50% load, 5mm size of glass beads, respectively. For 500mg/L naphthalene, nine days on the bioreactor with no glass beads and five days on glass beads bioreactors were required to complete depletion. The biodegradation rate is equal to 2.33, 7.29, and 7.85 mg/L-1hr-1 for bioreactors with no glass beads, 40% load with 6mm, and 50% load with 5mm glass beads, respectively. The specific growth rate was increased in the bioreactor with glass beads; it represents 0.031, 0.050, and 0.054 hr−1 for 300mg/L and 0.043, 0.061, and 0.065 hr−1 for 500mg/L respectively for the previously mentioned conditions. An artificial neural network was used to model naphthalene dissolution and biodegradation. A correlation coefficient of 99.2% and 98.3% were obtained between the experimental and predicted output values for dissolution and biodegradation, respectively, indicating that the ANN model could efficiently predict the experimental results. Time represents the most influential parameter on the dissolution and biodegradation treatment.

Study on a Novel Biodegradable and Antibacterial Fe-Based Alloy Prepared by Microwave Sintering

This research produced a porous Fe-8 wt.% Cu alloy by microwave sintering in order to achieve (i) an increased biodegradation rate, and (ii) an antibacterial function. The Fe-8Cu alloy had higher density, hardness and degradation rate (about 2 times higher) but smaller and fewer surface pores, compared to the pure Fe. The Fe-8Cu alloy had a strong antibacterial function (the antibacterial rates against E. coli were up to 99.9%) and good biocompatibility. This work provides a novel approach of alloy design and processing to develop novel antibacterial Fe-based alloys.