Interaction between Styrofoam and Microalgae Spirulina platensis in Brackish Water System

Plastic pollution and degradation pathways: A review on the treatment technologies

In recent years, the production of plastic has been estimated to reach 300 million tonnes, and nearly the same amount has been dumped into the waters. This waste material causes long-term damage to the ecosystem, economic sectors, and aquatic environments. Fragmentation of plastics to microplastics has been detected in the world's oceans, which causes a serious global impact. It is found that most of this debris ends up in water environments. Hence, this research aims to review the microbial degradation of microplastic, especially in water bodies and coastal areas. Aerobic bacteria will oxidize and decompose the microplastic from this environment to produce nutrients. Furthermore, plants such as microalgae can employ this nutrient as an energy source, which is the byproduct of microplastic. This paper highlights the reduction of plastics in the environment, typically by ultraviolet reduction, mechanical abrasion processes, and utilization by microorganisms and microalgae. Further discussion on the utilization of microplastics in the current technologies comprised of mechanical, chemical, and biological methods focusing more on the microalgae and microbial pathways via fuel cells has been elaborated. It can be denoted in the fuel cell system, the microalgae are placed in the bio-cathode section, and the anode chamber consists of the colony of microorganisms. Hence, electric current from the fuel cell can be generated to produce clean energy. Thus, the investigation on the emerging technologies via fuel cell systems and the potential use of microplastic pollutants for consumption has been discussed in the paper. The biochemical changes of microplastic and the interaction of microalgae and bacteria towards the degradation pathways of microplastic are also being observed in this review.

Oxidative degradation of pre-oxidated polystyrene plastics by dye decolorizing peroxidases from Thermomonospora curvata and Nostocaceae

Biodegradation of PS has attracted lots of public attentions due to its environmental friendliness. However, no specific PS degrading enzyme has been identified yet. Dye decolorizing peroxidases (DyPs) are heme-containing peroxidases named for the ability to degrade a variety of organic dyes. Herein, the abilities of two DyPs from Thermomonospora curvata (TcDyP) and Nostocaceae (AnaPX) to degrade PS were evaluated. Preoxidation methods by ultraviolet (UV) irradiation and chemical oxidants were developed to initially activate C-C bonds in the PS skeleton. DyPs degradation caused obvious etching and enhanced hydrophilicity of UV-PS films, and also generated new CO and C-OH groups. The cleavage of activated C-C bonds by DyPs was experimentally proven by analyzing the degradation products of UV-PS and model substrates. Furthermore, better pre-oxidation was obtained by using chemical oxidants KMnO₄/H₂SO₄ and ^mCPBA to oxidize PS materials in dissolved state. And AnaPX exhibited stronger degradation effects on KMnO₄/H₂SO₄-PS and ^mCPBA-PS by causing greater changes in functional groups CO, C-O, -OH groups and substituted benzenes and higher molecular weight reductions of 19.7% and 31.0%, respectively. To our knowledge, this is the first report on the identification of PS-degrading enzymes that provides experimental evidence.

Editorial for the Special Issue “Microplastics in Aquatic Environments: Occurrence, Distribution and Effects”

The large production and widespread daily consumption of plastic materials—which began in the last century—together with the often-inadequate collection and recycling systems, have made plastics and, consequently, microplastics (MPs) ubiquitous pollutants [...]

The effect of salinity on the interaction between microplastic polyethylene terephthalate (PET) and microalgae Spirulina sp

The increasing use of plastic over the last few decades has had an impact of plastic pollution in aquatic ecosystems. Plastic pollutions may be in the form of microplastics either from primary or secondary sources. These microplastics will indirectly affect human health through the food chain. This research was aimed at evaluating the interaction between microplastic and microalgae that are a source of food supplements. The experiment was conducted by investigating the impact of microplastic polyethylene terephthalate (PET) on microalga Spirulina sp. cultivated in fresh water and saline water (7 ppt salinity) for 14 days. The growth rate and morphology of Spirulina sp. and PET were evaluated. The result showed that the presence of PET and salinity decreased Spirulina sp. growth rate in cultivation by 0.174 day^-1 and reduced nutrient removal rates. However, the salinity system on medium-added PET was indicated that there are influences of Spirulina sp. against PET, where PET can be degraded by Spirulina sp. in the state of water with a salinity 7 ppt. FTIR graphic seems if there is any peak declination within PET augmentation in media with 0 ppt salinization. Nonetheless, the peak augmentation happened within PET augmentation in media with 7 ppt salinity. This signifies if there is an augmentation of PET salinization can be degraded by Spirulina sp. as the polysaccharide sources. PET is resistant to degradation due to its aromatic group. Based on the results scanning electron microscope (SEM), Spirulina sp. which growth with PET had a more uneven shape compared with a control variable.