جستجوی مقالات مرتبط با کلیدواژه « زیست توده » در نشریات گروه « پزشکی »

Today, polyethylene plastics have become a big problem of environmental health, i.e. excessive production of waste, and it has endangered the environment. But insects have come to the aid of the environment, and in the meantime, the large wax-eating moth (Galleria mellonella) is able to digest polyethylene plastic, polyester, aluminum foil, and even fabric masks with the help of the microbiome of its larva's stomach. This study was also designed to investigate the ability of G. mellonella larvae to remove polyethylene plastic .

First, G. melonella larvae were collected from Gonabad honey apiaries in June 2022. The larvae were reared in the Gonabad University of Medical Sciences medical entomology laboratory with beeswax and synthetic food in plastic boxes and dark rooms (temperature 25±2 oC and humidity 33%). To feed the larvae, pieces of plastic film were cut into diameters (10×10 cm) from the freezer, garbage, and shopping bag (so-called with handles) and placed on ten Petri dishes with a diameter of (8×8 cm) containing ten larvae. Another petri dish (with a hole for larvae to breathe) was placed on the polyethylene films. The produced biomass of larvae related to each type of plastic was analyzed separately with Fourier transform infrared spectrometry (FT-IR).

Analysis of 8 types of biomass produced by larvae feeding from wax (control) compared to polyethylene plastics (target item) with FT-IRIt revealed functional groups C-CL, C=O, C=C, R-OH, CH2, -C-C-, which is a sign of polyethylene plastic degradation. Also, the comparison of the amount of plastic removal among the larvae fed on different types of polyethylene film revealed a significant difference (P<0.05).

G. melonella larvae as a biological method can be effective in removing plastic from nature in the future.

CO2 is the main cause of greenhouse effect. Previous studies have shown that CO2 in methane and coal flue gas can lead to microalgae growth. The aim of this research was to study the CO2 biofixation by Spirulina and injecting kerosene flue gas. A photo bioreactor was fabricated in which kerosene flue gas and air were separately injected. The photo bioreactor was filled by growth medium without carbon source. Light source was four fluorescent lamps (10 Klux intensity) operated in continuous and intermittent modes. The concentration of CO2 was chosen in the range of 580 to 6000 ppm that was measured by NDIR CO2 detector. The initial concentration of algae was 20 mgL-1. The algal biomass production was measured during the experiment. The maximum production of algae by air and kerosene flue gas containing 5500 ppm CO2 using artificial intermittent light was 0.07 and 0.41 gL-1 d-1 and maximum concentrations of biomass were 0.25 and 1.63 gL-1, respectively. CO2 biofixation rates were between 2.27% and 4.03% at different runs. Biomass productivity with intermittent light was 15% less than continuous light and it reached 1.91 gL-1 with 5500 ppm CO2 using continuous light. In this study, the ability of a photo bioreactor was confirmed in the removal of CO2. Also, increase in CO2 contributes to increase in biomass production.

As a green fuel and environmentally friendly energy, biodiesel has recently attracted much attention and efforts are ongoing to optimizing biodiesel production from microalgae’s. The aim of this study was to determine the appropriate method of dewatering and drying biomass and selecting a suitable organic solvent for extraction lipids from biomass. After culturing Nannochloropsis Oculata in Gillard F/2 medium and reaching at the end of the stationary growth phase, algal biomass was separated from aqueous by centrifuge and drying in three fore, air-dried and lyophilized. Lipid extractions of each sample was performed using soxhlet apparatus and three solvents including diethyl ether, n-hexane and n-pentane. At each stage, the quantity and quality of the extracted lipids was determined by gas chromatography. In all three drying methods, palmitic acid and palmitoleic acid were significantly the main fatty acid composition of microalgae. The fatty acid composition of palmitic acid extracted by diethyl ether was significantly more than the other two solvents. Maximum production of triglyceride was observed in air dried and lyophilized (using diethyl ether solvent) microalgae as 75.03 and 76.72 % of fatty acid respectively. The use of lyophilized method for dewatering and drying of biomass and diethyl ether as solvent for the extraction of lipids from biomass yielded more compared with other methods studied in this paper and would be more efficient in research works related to the production of biodiesel from microalgae’s lipid.

Nowadays, excessive pop ulation growths, urbanization, and cons-umption of fossil fuel lead to the envi-ronmental pollution and damages. So, there is a significant attention to the usi-ng of cleaner fuels such as biogas. Man-y countries use biomass in order to pro-duce biogas as a source of energy. But in Iran, biomass usage has not been yet taken into account. It may be due to the lack ofthe biogas technology and cost. This study aimed to introduce a new ty-pe of semi-automatic green biogas ma-chinewith high efficiencyand enhance its output. In our machine, new mechanical and electronic parts de-vised and economically made. These parts were included: 1- electronic senso-rand monitoringpartfor temperature, hu- midity and methane variables, 2- seven-layer flexible gas tank, and 3- electronic safety valve with controllable gage for escaping excessive gas. The results of the experime-ntal usage of machine showed that the extent of produced gas was acceptable, saf-e, manageable and economic. Discussion & We could im-prove its efficiency throughcontrolling and changing differentvariablesin trial and error manner. So, useful results ob-tained from this machine showed that this device can be used to enhance the efficiency of methane production by 25 %.