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Investigation of the Mechanical Strength of Cell-plastics Fabricated Using Unicellular Green Algal Cells and Varying Weight Ratios of Biodegradable Polybutylene Succinate
Akihito Nakanishi,
Kohei Iritani,
Yuri Sakihama,
Marina Watanabe
Issue:
Volume 5, Issue 4, December 2020
Pages:
159-164
Received:
14 October 2020
Accepted:
23 October 2020
Published:
11 November 2020
Abstract: Petroleum-derived plastics are currently indispensable; however, they are non-recyclable and exhaustible. Despite global progress in the research and development for biodegradable green plastics using recyclable resources, green plastics are unable to replace petroleum-derived plastics so far because of the costs involved in the extraction and purification processes. Due to the increasing demand for the development of innovative green plastics, cell-plastic composed of the green alga Chlamydomonas reinhardtii as an ingredient and biodegradable compounds as fillers was proposed as a novel green plastic. For a carbon-recycling system in the future, C. reinhardtii is advantageous due to higher growth activity using CO2 gas in atmosphere compared to other terrestrial plants. In addition, the rigidity of its cell wall would prevent the reduction of a mechanical strength of the cell-plastics. Green plastics made of organic polymers are expensive because of high producing cost. On the other hand, the plastics made of green algae, instead of organic polymers, would be expected reducing the price. Thus, the purpose of this study was to clarify whether the cell-plastics produced by substituting organic polymers with algal cells could perform mechanical and physical properties similar to existing plastics products. As a filler for cell-plastics, biodegradable polybutylene succinate (PBS), which form a self-standing film, was chosen in this study. PBS cell-plastics were examined for their following mechanical and physical properties: Young's modulus, tensile strength, thermal analysis, and surface hydrophilicity. PBS cell-plastic (1:1) composed of 50% PBS (w/w) exhibited the potential to replace petroleum-derived plastics such as low-density polyethylene and polyvinyl chloride. This study introduces the practical possibility of PBS cell-plastics as green plastics.
Abstract: Petroleum-derived plastics are currently indispensable; however, they are non-recyclable and exhaustible. Despite global progress in the research and development for biodegradable green plastics using recyclable resources, green plastics are unable to replace petroleum-derived plastics so far because of the costs involved in the extraction and puri...
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Interactions of Organic Acids with Staphylococcus aureus and MRSA Strains from Swine Mandibular Lymph Node Tissue, Commercial Pork Sausage Meat and Feces
Ross Carlton Beier,
Kathleen Andrews,
Toni Lee Poole,
Roger Bruce Harvey,
Tawni Lyn Crippen,
Robin Carl Anderson,
David James Nisbet
Issue:
Volume 5, Issue 4, December 2020
Pages:
165-183
Received:
30 October 2020
Accepted:
11 November 2020
Published:
19 November 2020
Abstract: Staphylococcus aureus is a Gram-positive bacterium affecting human health, and a major cause of skin infections, endocarditis, meningitis, and sepsis. Methicillin-resistant S. aureus (MRSA) is a worldwide health concern, occurs in food animals, is consistently found in swine, and improved strategies are needed to ensure the removal of MRSA from food products. A total of 164 S. aureus strains were isolated from swine mandibular lymph node tissue, commercial pork sausage meat, and feces. These strains were tested for methicillin-resistance, and 7 of the strains isolated from the mandibular lymph node tissue and pork sausage meat were resistant to cefoxitin and oxacillin, and tested positive for staph specific rRNA and for the mecA gene and are therefore, MRSA strains. An intracellular MRSA contamination of 8.2% within swine lymph node tissue and 5.8% MRSA contamination in pork sausage meat was demonstrated. Lymph node tissue may be utilized in producing pork sausage; therefore, the prevalence of MRSA in final pork products may not only be caused by surface contamination, but by internal tissue infection. The strains were tested for susceptibility to six organic acids (OAs) citric, L-lactic, butyric, acetic, propionic, and formic acid. The pH was determined at each of the minimum inhibitory concentrations (MICs) observed for the S. aureus strains. The Henderson-Hasselbalch equation was used to calculate the ratio of the undissociated to dissociated OA concentrations, and the molar concentrations of each were calculated from the total OA present and the ratio. Inhibition of S. aureus did not correlate with pH or the undissociated OA concentrations, but it did correlate with the dissociated OA concentrations. A dissociated OA concentration of 21 mM was successful for inhibiting the S. aureus strains tested. Studies must be conducted in vivo to confirm this concentration value. Acetic, butyric, formic, and propionic acid were the most effective OAs tested against S. aureus.
Abstract: Staphylococcus aureus is a Gram-positive bacterium affecting human health, and a major cause of skin infections, endocarditis, meningitis, and sepsis. Methicillin-resistant S. aureus (MRSA) is a worldwide health concern, occurs in food animals, is consistently found in swine, and improved strategies are needed to ensure the removal of MRSA from foo...
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Isolation and Molecular Identification of a Novel Tyramine-producing Bacterium, Rummeliibacillus pycnus
Omnia Morsy,
Mervat Amin Kassem,
Abeer Elsayed Abd El-Wahab,
Nelly Mostafa Mohamed
Issue:
Volume 5, Issue 4, December 2020
Pages:
184-192
Received:
6 November 2020
Accepted:
21 November 2020
Published:
30 November 2020
Abstract: Decarboxylation of tyrosine through tyrosine decarboxylase enzyme produces tyramine which may represent a serious threat to public health, as it may cause severe toxicological effects. Intake of tyramine will invariably result in acute symptoms as it can rapidly gain access to the bloodstream and to various organs where it can act as a vasoactive agent through interaction with the sympathetic noradrenergic nerve terminals innervating cardiac and vascular smooth muscle tissues. This research is focusing on tyramine as one of the indicators of inappropriate food storage and processing conditions of milk products. In the current study, 25 dairy product samples were collected from local markets in Alexandria, Egypt, and were analyzed for bacterial contamination and prevalence of tyramine-producing bacteria by PCR using degenerate primers (DEC5/DEC3). While cream was the most contaminated dairy product, balady yogurt samples were the least contaminated ones. Different types of tyraminogenic bacteria have been isolated from the collected dairy products. Cream samples were contaminated with the widest variety of tyraminogenic bacteria among the isolated samples including Bacillus pumilis, Escherichia coli, Enterococcus faecium, and Proteus mirabilis. A total of 35 strains harboring tyrosine decarboxylase gene were detected with the identification of a novel tyramine-producing strain: Rummeliibacillus pycnus. These results indicate the promising application of degenerate primers (DEC5/DEC3) to detect tyramine production in dairy products, a goal that has been regarded as a challenge by manufacturers.
Abstract: Decarboxylation of tyrosine through tyrosine decarboxylase enzyme produces tyramine which may represent a serious threat to public health, as it may cause severe toxicological effects. Intake of tyramine will invariably result in acute symptoms as it can rapidly gain access to the bloodstream and to various organs where it can act as a vasoactive a...
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Production, Characterization and Evaluation of Bacterial Protease as a Potential Additive to Enhance Detergency of Endod
Issue:
Volume 5, Issue 4, December 2020
Pages:
193-202
Received:
19 November 2020
Accepted:
3 December 2020
Published:
16 December 2020
Abstract: At present alkaline proteases are widely used in the detergent, leather tanning, pharmaceutical, food, and feed processing industries. Although proteases are found in all living organisms (plant, animal, and microorganisms), the bulk of commercially important enzymes are from microorganisms. The aim of this study was to isolate protease producing bacteria, characterize the enzyme, and evaluate potential application as detergent additive to enhance the washing performance of endod berries. Different bacterial strains were isolated from soil and screened using an alkaline casein agar media. One isolate designated as aau 2106 was selected for further study because of its high proteoliytic activity, level of enzyme production and, ability to grow under solid state fermentation (SSF). Cultivation condition for the production of the enzyme under SSF, such as, moisture content, nitrogen content, and incubation period were optimized. The enzyme was active in the pH range of 6 to 10.5, temperature of 40 to 75°C. And optimum in; 96h incubation period, 1:1 ratio of moisture content and, casein in the production of enzyme under SSF and the enzyme was stable in the presence of endod and commercial detergents. The potential of the enzyme as a detergent additive was tested by adding the protease (57 U/g) in detergent formulations and used to clean pieces of cloth stained with blood and egg. Addition of the enzyme improved the cleaning efficiency of both endod and commercial detergents. This indicates that enzyme supplementation of endod could result in the development of an ecofriendly detergent.
Abstract: At present alkaline proteases are widely used in the detergent, leather tanning, pharmaceutical, food, and feed processing industries. Although proteases are found in all living organisms (plant, animal, and microorganisms), the bulk of commercially important enzymes are from microorganisms. The aim of this study was to isolate protease producing b...
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Isolation of Antibiotics Producing Actinobacteria from Biowaste Soil Samples
Issue:
Volume 5, Issue 4, December 2020
Pages:
203-206
Received:
19 November 2020
Accepted:
4 December 2020
Published:
16 December 2020
Abstract: Actinomycetes are a filamentous bacterium that belongs to the phyla actinobacteria. They are one of the most attractive sources of antibiotics. In this study, Isolation of Actinomycetes strain was obtained by serial dilution method and grown on starch casine agar (SCA). Soil sample were collected from Addis Ababa Science and Technology University (AASTU) and tests were performed to assess the presence of Actinomycetes using macroscopic observation and microscopic methods. Potential actinomycete isolates were also identified as gram positive by using Gram staining technique. The five out of twelve isolates showed coiled and rod shaped spore resembling the genus Streptomycets and antibacterial activities were evaluated for their antibacterial activity. Three out of five potential actinomycete isolates (isolate number 2, 4, and 5) showed anti bacteria activity, of which one isolate (isolate number 5) showed good inhibitory result when tested against two strains of microorganisms (E.coli and S. aures). Isolate 5 was found to exhibit significant antibacterial activity against the gram positive bacteria, Staphylococcus aures. It is concluded that the biowaste soil sampled from AASTU campus harbors a variety of potential antibiotic producing Actinomycetes, which can be used up for further exploration.
Abstract: Actinomycetes are a filamentous bacterium that belongs to the phyla actinobacteria. They are one of the most attractive sources of antibiotics. In this study, Isolation of Actinomycetes strain was obtained by serial dilution method and grown on starch casine agar (SCA). Soil sample were collected from Addis Ababa Science and Technology University (...
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