Spirulina Cultivation Under Different light-emitting Diodes for Boosting Biomass and Protein Production.

Microalgae biomass and pigments have a high economic value due to their many biological and commercial applications. In this sense, Spirulina platensis was grown under different (LEDs) light-emitting diodes. The current examination aims to increase the biomass production of S. platensis by formulating an optimal growth condition under different LED lights. Light-emitting diodes have a precise wavelength that has an encouraging effect on microalgae biomass production. For this purpose, the light intensity of 3000 lx was used to illuminate the culture medium, resulting in enhanced S. platensis biomass production. The highest optical density of 0.576 and dry cell weight of 0.343 g/L was recorded for the white light-emitting diode, and the red light-emitting diode, the optical density of 0.479 and dry cell weight of 0.321 g/L was recorded. The highest protein content of 66.10 ± 0.44% was registered with a blue light-emitting diode, followed by a white light-emitting diode with a protein content of 60.86 ± 0.39%. This research is an essential step in defining the light condition that might be useful to increase the biomass production of S. platensis. The study's findings demonstrated that exposure to various light-emitting diode colors could enhance both the quality and quantity of biomass produced in S. platensis cultures and encourage the use of light-emitting diodes as a light source for S. platensis farming without any undesirable effects on growth.

Unlocking the benefits of split gill mushroom: Chemical analysis and prebiotic properties of schizophyllan extract.

The edible split gill mushroom is considered both a nutritive and therapeutic superfood, as well as rich in schizophyllan and protein. Prebiotic properties and other biological effects distinguish the schizophyllan (ß-glucan). Thus, this research investigates the identity of the mushroom strain, the nutritional composition of this mushroom, and the schizophyllan extract for further analysis, including its prebiotic activity and so on. The experimental results revealed that this mushroom was identified as Schizophyllum commune, comprising more excellent carbohydrates, protein, crude fiber, lower fat, and no heavy metal detection. Moreover, this extract consisted of pharmaceutical hydrophobin (14.0-18.5 kDa), lectin protein (21-35 kDa), bioactive purpurin or red pigment, including the prebiotic ß-glucan stimulating the proliferation of probiotic bacteria isolated from yogurt. Therefore, both S. commune and the schizophyllan extract can be used as a prebiotic candidate, functional food, and nutraceutical product.

Effect of Photoperiod and White LED on Biomass Growth and Protein Production by Spirulina.

The constant increase in demand for food, valued bio-based compounds and energy demand has prompted the development of innovative and sustainable resources. New technologies and strategies must be implemented to boost microalgae biomass production, such as using different photoperiods along with (LED) light-emitting diodes to stimulate biomass production and boost profits. This work investigates the cultivation of blue-green microalgae (Spirulina) in a closed lab condition. The current study aims to boost Spirulina biomass production by creating ideal growth conditions using different photoperiods (12:12; 10:14; 14:10) light/dark with a constant light intensity of 2000 lx from White LED lights. The obtained optical density and protein content was highest for photoperiod 14L: 10D and values were 0.280 OD, with a protein content of 23.44 g/100 g, respectively. This study is a crucial first step in identifying the best photoperiod conditions to help S. platensis produce more biomass. The study results showed that increasing photoperiod for S. platensis farming can improve the quality and amount of biomass generated in those cultures without negatively affecting growth.

Current application of seaweed waste for composting and biochar: A review.

To address the origins of ocean acidification, seaweed aquaculture is emerging as a key biosequestration strategy. Nevertheless, seaweed biomass is involved in developing food and animal feed, whereas seaweed waste from commercial hydrocolloid extraction is dumped in landfills, which together limit the carbon cycle and carbon sequestration. This work sought to evaluate the production, properties, and applications of seaweed compost and biochar to strengthen the "carbon sink" implications of aquaculture sectors. Due to their unique characteristics, the production of seaweed-derived biochar and compost, as well as their existing applications, are distinct when compared to terrestrial biomass. This paper outlines the benefits of composting and biochar production as well as proposes ideas and perspectives to overcome technical shortcomings. If properly synchronized, progression in the aquaculture sector, composting, and biochar production, potentially promote various Sustainable Development Goals.

Biorefining and biotechnology prospects of low-cost fish feed on Red tilapia production with different feeding regime.

This study aimed to decrease the production cost and increase tilapia yield with a feeding regime. The trial was divided into four treatments with three replications followed by the feeding frequency in monosex male Nile tilapia with an average initial weight of 17.86-18.40 g/fish cultured on a net cage in the earth pond for three months. Fish fed with 18% protein supplemented with 5% protein concentrate. The first month was used by 32% protein feed twice per day (T1, control), fish were fed twice per day every other week (T2), fish were fed twice per day per week (T3), and fish were fed twice per day per week (T3). Fish fed twice per day per week are now fed twice per day (T4). These results revealed that T2 fish had the highest growth performance and most protein consumption (P < 0.05). Moreover, fish in T2 has the lowest production cost and highest benefit-cost ratio (B/C ratio) (P < 0.05). The highest percentage of edible meat in T2 was P < 0.05, but the proximate analysis was close for all three groups (P > 0.05). As a result, it is necessary to ensure that Nile Tilapia culture has sufficient protein and nutrition control. This will allow for both high growth and low cost. Fish health and quality were positively affected by a perfect protein-containing feeding regimen. In fish fed with 18% protein and 5% protein concentrate for the first month, followed by 32% protein feed twice every other day and then with 18% protein.

Development of aeration devices and feeding frequencies for oxygen concentration improvement in 60-tones freshwater recirculating aquaculture and biofloc ponds of Asian seabass (Lates calcarifer) rearing.

This research aimed to improve the technique to maintain the oxygen content of two freshwater Asian sea bass (Lates calcarifer) culture systems (recirculating aquaculture system; RAS; and biofloc system; Floc). The dissolved oxygen content was increased by using a blower with flexible rubber hose aerators. For the first study, the effectiveness of oxygenation was investigated. As a result, the aerator and flexible rubber hose are appropriate for increasing oxygen levels in the fish pond. An air pump with a flexible aeration tube (400 W), one set of ejector aerators (250 W), and two sets of ejector aerators (250 × 2 W) were used to test the efficiency of oxygenation. In addition, the performance of the RAS and Floc systems, off-flavor (geosmin and MIB) in taints, and economic returns were assessed. This study found that after monitoring two 60-tonne concrete ponds with one set of blowers (RAS1) and two sets of blowers (RAS2) connected by a flexible rubber tube; feeding frequency (2 and 6 times/day). However, daily dissolved oxygen fluctuated in the RAS, and this value went to its lowest after post-feeding. Dissolved oxygen was higher than the two-meal pack per day when the feeding was expanded to six meals. This aeration device could provide dissolved oxygen enough for 900 kg fish/400 W. Seabass raised in the freshwater RAS system had higher yields and growth rates than those raised in the biofloc pond systems. In addition, low off-flavors trained was observed. Therefore, this research could improve aeration management by aeration devices and increase feeding frequency while developing freshwater-adapted Asian seabass production.

Synthesis of two different zinc oxide nanoflowers and comparison of antioxidant and photocatalytic activity.

Nanoflowers are a newly developed class of nanoparticles that show flower-like structures and attract much attention due to their simple preparation methods, high stability, and increased efficiency. The aim of the study is to investigate a strong alternative to reduce the severity of infection and increase the treatment of wastewater by exhibiting biofilm inhibition in medical and environmental applications of the ZnO-NFs with two different shapes. ZnO-NFs were synthesized by two different processes hydrothermal method (named ZnO-NF1) and the precipitation method (named ZnO-NF2). ZnO-NFs produced by two different synthesis methods were compared for the photocatalytic and antioxidant efficiency. The effects of Reactive Red 180 (RR180) and Basic Red 18 (BR18) dyes concentration, photocatalyst amount, and reaction time were investigated on dye removal efficiency for photocatalytic experiments. The color was completely removed for 25 mg/L BR18 and RR180 dyes for 75 min and 90 min, respectively, using 1.5 g/L photocatalyst amount using ZnO-NF1. However, 59.18% dye removal efficiency was obtained for 90 min by using a 1.5 g/L ZnO-NF2 photocatalyst for 25 mg/L BR18 dye removal, while a dye removal efficiency of 90.00% was detected for 90 min using 2 g/L ZnO-NF2 for 25 mg/L RR180 dye. Then, comparison of general properties such as antibacterial, antibiofilm, microbial cell viability, DNA fragmentation, antioxidant activities, and antimicrobial photodynamic therapy of ZnO-NFs were investigated. The antioxidant activity of ZnO-NF2 was found to be higher than ZnO-NF1 at each concentration (82.32% and 87.18% for ZnO-NF1 and ZnO-NF2, respectively, at 200 mg/mL).

Photocatalytic activity of calcined chicken eggshells for Safranin and Reactive Red 180 decolorization.

One of the most important problems affecting the environment today is the inability to adequately treat wastewater containing dyes. Among of the many treatment processes used in the treatment of dye-containing wastewater, photocatalytic based wastewater treatment processes attract the attention of scientists as a new, economically feasible, and promising approach which has been in practice for a few decades. However, in order to use these processes in wider areas, cheap and effective catalysts are still being developed today. In this study, the photocatalytic activity of eggshell-CaO produced from waste chicken eggshells was investigated for decolorization of Safranin (Basic Red 2) and Reactive Red 180 (RR180) dyes. First, sintering process was applied to the waste chicken eggshells at different temperatures (300, 600, 900 °C) in order to observe CaO formation from the eggshells. Second, the parameters such as photocatalyst amount, pH, concentration of dyes, and reaction time were optimized on dye removal efficiency in photocatalytic experiments. The optimum conditions were performed under visible light and found to be 1 g/L of catalyst amount (sintered at 900 °C), original solution pH (6.80 for Safranin and 6.60 for RR180), and 5 mg/L of dye concentration. The photocatalytic removal efficiencies of Safranin and RR180 dyes were 100% and 97.90%, respectively, under the determined optimum experimental conditions. The adsorption efficiency of the dyes that could be realized during the photocatalytic experiment was measured as 20.99% and 9.99% for Safranin and RR180 dyes, respectively.

Biohydrogen production using algae: Potentiality, economics and challenges.

The biohydrogen production from algal biomass could ensure hydrogen's sustainability as a fuel option at the industrial level. However, some bottlenecks still need to be overcome to achieve the process's economic feasibility. This review article highlights the potential of algal biomasses for producing hydrogen with a detailed explanation of various mechanisms and enzymes involved in the production processes. Further, it discusses the impact of various experimental parameters on biohydrogen production. This article also analyses the significant challenges confronted during the overall biohydrogen production process and comprehends the recent strategies adopted to enhance hydrogen productivity. Furthermore, it gives a perception of the economic sustenance of the process. Moreover, this review elucidates the future scope of this technology and delineates the approaches to ensure the viability of hydrogen production.

Effect of biogas sludge meal supplement in feed on growth performance molting period and production cost of giant freshwater prawn culture.

The worldwide prawn industry strives for better production and environmental sustainability. Shrimp feed is one of the most expensive aquaculture inputs; therefore, it must be cost-effective and environmentally safe. Fish meals in aquaculture are becoming unsustainable due to the cost and environmental concerns. The effects of a biogas sludge meal supplement in feed on freshwater prawn productivity were studied. This study aimed to examine the growth, survival rate, yield, feed conversion ratio, and molting period of giant freshwater prawns (Macrobrachium rosenbergii) fed with and without biogas sludge a low-cost resource. The four treatments were T1 (0% biogas sludge), T2 (10% biogas sludge), T3 (20% biogas sludge), and T4 (30% biogas sludge). Protein content ranged from 26.7 to 27.4% in the experimental diets. The experiment was conducted in 3 × 3x1.5 m cages in an earthen pond for 80 days. The data shows that freshwater prawn growth performance did not differ significantly across treatments (P > 0.05). Biogas sludge has been demonstrated to be a low-cost feed component for freshwater prawns. Regarding survival, productivity, and feed conversion ratio, T2 (10% biogas sludge) outperformed the other two. As a result of the research, it was determined that 10% of biogas sludge might be used as a low-cost freshwater prawn feed option. The molting period of freshwater prawns fed biogas-containing feed was investigated at various levels. Freshwater prawns grown in baskets in a pond at 32.2 °C for a trial period of 90 days were molted differently (P > 0.05). The molting periods for Tl, T2, T3, and T4 were 19, 18, 19.8, and 20.8, respectively. In addition, the research suggests efficient and long-term methods for supplying nutrient-dense prawn feed to aquaculture production systems.

Physiological response of Simocephalus vetulus to five antibiotics and their mixture under 48-h acute exposure.

Antibiotics, widely known as major environmental xenobiotics, are increasingly being released into ecosystems due to their essential functions in human health and production. During the COVID-19 pandemic waves, antibiotic use increases remarkably in treating bacterial coinfections. Antibiotics were initially expected only to affect prokaryotes, but recent research has shown that they can disturb the biological systems of eukaryotes, especially vulnerable aquatic creatures, through both direct and indirect processes. However, their toxicity to the freshwater cladoceran Simocephalus vetulus, an essential link in the aquatic food web, has never been evaluated. The effects of four fluoroquinolones (ciprofloxacin: CFX, ofloxacin: OFX, gatifloxacin: GFX, delafloxacin: DFX), tetracycline (TET), and a mixture of these medicines (MIX) on S. vetulus thoracic limb rate (TLR) were examined in this study. After S. vetulus was exposed to 20 and 40 mg GFX L-1, 90% and 100% mortality rates were recorded. At 2.5-10 mg L-1, GFX dramatically lowered the TLR of S. vetulus, resulting in a median effective concentration of 9.69 mg L-1. TLRs increased when the organisms were exposed to 10-40 mg L-1 of CFX and 1.25-40 mg L-1 of OFX. However, DFX and TET exposures did not affect TLRs. Exposure to MIX reduced TLR only at 40 mg L-1, suggesting an antagonistic interaction among the five pharmaceuticals. This study demonstrated that S. vetulus physiological responses to antibiotics, even in the same class, are complex and elusive. Beyond a common additive concentration principle, the antagonistic interaction of antibiotic mixture indicates a high level of uncertainty in terms of ecological dangers. We initially introduce S. vetulus to ecotoxicological studies of antibiotics, presenting the species as a low-cost model for physiological investigations of environmental xenobiotics.

Advancement of fermentable sugars from fresh elephant ear plant weed for efficient bioethanol production.

Bioethanol is considered one of the most promising next-generation automotive fuels, as it is carbon neutral and can be produced from renewable resources, like lignocellulosic materials. The present research investigation aimed to utilize the elephant ear plant, a hazardous plant (weed) also considered an invasive species, as a font of non-edible lignocellulosic biomass for bioethanol production. The freshly collected elephant ear plant (leaves and stalk) was chopped into small pieces (1-2 cm) and then homogenized to a paste using a mechanical grinder. The sample pretreatment was done by flying ash for three different time durations (T1 = 0 min, T2 = 15 min, and T3 = 30 min) with 3 replications. All treatment samples were measured for total sugar and reducing sugar content. The concentration of reducing sugar archived was T1 = 0.771 ± 0.1 mg/mL, T2 = 0.907 ± 0.032 mg/mL, and T3 = 0.895 ± 0.039 mg/mL, respectively. The results revealed that the chemical composition was different among treatments. The hydrolysis was performed using cellulase enzymes at 35 °C for the hydrolysis process. The hydrolysate was inoculated with 1% of S. cerevisiae and maintained at room temperature without oxygen for 120 h. Bioethanol concentration was measured by using an ebulliometer. The efficient ethanol percentage was 1.052 ± 0.03 mg/mL achieved after the fermentation. Therefore, the elephant ear plant invasive weed could be an efficient feedstock plant for future bioethanol production.

Microalgae cultivation in wastewater effluent from tilapia culture pond for enhanced bioethanol production.

The large number of wastewaters are generated because of the various production processes. Vegetable and fish processing can be considered an important industry for wastewater generation. The essential method for completing this waste is to digest the organic matter using anaerobic digestion followed by aerobic wastewater treatment processes; however, wastewater from tilapia culture pond retains considerable quantities of inorganic substances, particularly nutrients like nitrogen and phosphorus. The optimal conditions for cultivating Chlorella vulgaris from wastewater treatment effluent from tilapia culture pond were investigated in this study. The appropriate conditions were found to be 10% initial stock suspension, 20 cm depth, and 12 days of culture conditions. C. vulgaris had an optical density of 0.649, a cell density of 17.68 × 105 cells/mL, and biomass of 0.376 ± 94.21 mg/L after cultivation. Discharged wastewater from the fishpond was utilized for the improved growth of microalgae and obtained biomass was used for bioethanol production. This study verified that fishpond wastewater is the best source of nutrients for algal mass production and biofuel applications.

Biomass generation and biodiesel production from macroalgae grown in the irrigation canal wastewater.

The wastewater concentration is commonly acceptable for macroalgae growth; this process consumes water and is applicable for bioremediation. This study evaluated biodiesel's potential production from freshwater macroalga, Nitella sp., using batch experiment. Algae were collected from wastewater saturated from irrigation canals. Water quality and algae growth environment characteristics were monitored and analyzed. COD and BOD values were 18.67 ± 4.62 mg/L and 5.40 ± 0.30 mg/L, respectively. The chemical composition contents were high, demonstrating that water quality and sufficient nutrients could support algae growth. Oil extraction was estimated by the room temperature and heat extraction methods. The biodiesel in room temperature treatment was 0.0383 ± 0.014%, and in heat, extraction treatment was 0.0723 ± 0.029%. Results confirmed that the heat extraction treatment gave a high amount of oil and biodiesel yield. Gas chromatography/mass spectrometry (GC/MS) was used to analyze fatty acid methyl esters (FAME). Results revealed that 9-octadecane was a major portion of the substance. The obtained results confirmed that the wastewater contains many elements that can be utilized for dual-mode, like bioremediation and enhanced macroalgae growth for biodiesel production. Therefore, macroalgae grown in canal wastewater were highly feasible for use in sustainable biodiesel production.

Chronic ecotoxicology and statistical investigation of ciprofloxacin and ofloxacin to Daphnia magna under extendedly long-term exposure.

Ciprofloxacin (CFX) and ofloxacin (OFX) are two of the most often used fluoroquinolone antibiotics, and their residues are found in large amounts in various aquatic settings. However, the toxicity tests of CFX using eukaryotic organisms such as Daphnia magna are inadequate, and the test result of OFX is currently unknown. Therefore, the chronic toxicity test for D. magna was performed during 42 days under exposure to CFX and OFX concentrations of 50, 500, and 5000 µg L-1. All exposure conditions did not cause mortality for D. magna. CFX exposure at 500 µg L-1 resulted in an earlier oogenesis date and increased brood size in the second birth. The Poisson-based generalized linear mixed-effects model revealed that the reduction of fertility was statistically significant for the CFX and OFX exposures at 5000 µg L-1. On the other hand, the production of dead eggs as offspring degradation was also found significantly as maternal D. magna exposed to antibiotics at 5000 µg L-1. In addition, following long-term exposure to antibiotics, maternal adaptation to antibiotics was established for offspring deterioration and fertility. However, the OFX exposure showed that the fertility-suppressed effects continued for a longer period than the CFX exposure. Although no rational explanation has yet been given for the more substantial effect of OFX on reducing fertility than CFX, molecular cell biology and symbiotic microbial flora derived from previous studies could explain our ecotoxicological results. This study is the first report for the OFX chronic toxicities on D. magna by comparing it to the toxicity of CFX. Our study contributes to guiding the future impact assessment of fluoroquinolone antibiotic pollution on ecosystems, including the need for new statistical methods in ecotoxicological studies.

Sustainable development of feed formulation for farmed tilapia enriched with fermented pig manure to reduce production costs.

Aquaculture is often referred to as "livestock production" with a proper "future-facing" strategy. Fish productivity varies greatly, and feeding is a significant expense for farmers. Despite the increased interest in waste valorization, a biorefinery strategy to reduce feed costs has been developed. Therefore, the objectives of this study were to determine the growth of Nile tilapia (Oreochromis niloticus) in cement ponds fed with feed formulas containing fermented pig manure in various ratios and to verify the digestibility of Nile tilapia fed with fermented pig dung-based diets. The 120-days experiments were conducted in 20 cement ponds to determine the nutritional content of pig manure collected from a fermented system and the permissible level of digested manure to be utilized as a raw material to formulate alternative tilapia feed. Fermented pig manure (diet) has a high protein content and other nutrients, including nitrogen, phosphorus, potassium, copper, manganese, and zinc. Furthermore, the quantities of phytoplanktons in cement pond water associated with manure diets of 0, 5, 10, and 15% are estimated. The diet with 15% manure produced the most weight gain and yield (75.3 g and 1002.80 g, respectively). The findings of this study emphasize the new technique of feeding fermented pig manure to fish, opening up a wide range of possibilities for achieving a sustainable protein source for aquaculture.

Stimulation of natural enzymes for germination of mimosa weed seeds to enhanced bioethanol production.

Depleting fossil fuels target plant weeds which have the potential to be converted into efficient biofuels. In this study, mimosa seeds were utilized as a substrate for bioethanol production. This investigation was divided into three parts: breaking dormancy of seeds, mimosa seeds germination, and bioethanol production from mimosa seeds. Seed dormancy breaking was initiated by seeds soaked in hot distilled water to analyze the sugar quantity. Sugar content was measured relevance with root length results. According to results, root length obtained revealed that at 0.5-1.0 cm for root size has the most sugar availability. It was revealed that the total sugar 548.21 g/L and reducing sugar has a concentration of 248.67 g/L. Therefore, the broken dormancy of seeds using hot water at 95 °C for 10 min with a root length of 0.5-1 cm was used for ethanol fermentation. Ethanol fermentation was done by free yeast cell and immobilized yeast by injecting yeast directly. The ethanol yield was measured on the 3rd day of every fermentation. Results showed that the free cell yeast during the 1st day of fermentation afforded an ethanol production of 57.574 g/L, while the yield for immobilized yeast was 60.714 g/L. Consequently, the ethanol yield on the 2nd day of fermentation from the directly injected immobilized yeast was 60.088 g/L. Results revealed that the immobilization of yeast cells in fermentation provided a higher probability for bioethanol yield and could be utilized as a baseline for future bioethanol production. Stimulation of natural enzymes by germination of seeds for enhanced bioethanol production will be a novel approach towards next-generation biofuels.

Appropriateness of waste jasmine flower for bioethanol conversion with enzymatic hydrolysis: sustainable development on green fuel production.

Utilized and waste jasmine flower contains a high portion of organic carbohydrate and other organic acids, making it a suitable substrate for bioethanol production. This study was designed to estimate the prospective of waste jasmine flower biomass applied with chemical (alkaline) and thermal pretreatment applied on samples through bioethanol production efficiencies. Therefore, pretreatment and enzymatic hydrolysis are directed to disrupt the complex cell wall layer and improve the accessibility towards polysaccharide fraction. Also, applying response surface methodology tools during fermentative bioethanol production to study the interactive effects of different bioprocess variables for higher bioethanol yield in batch small and large scale model is discussed. The immobilized yeast between jasmine found that jasmine sugar utilization was 50%. The jasmine flower's ethanol production was 6.54 g/L and after distillation of jasmine was 31.40 g/L at pH 4.5. Results showed that this immobilized yeast method could be successfully used for bioethanol production from waste jasmine flower.

Optimization of pretreatment condition for ethanol production from Cyperus difformis by response surface methodology.

This study investigated the potential of a new material, so-called small-flowered nutsedge, for bioethanol production. This plant causes the huge loss of rice yield as it competes nutrients, sunlight and other necessary elements with rice plant to grow. The project plans to transform its biomass into valuable product and bring profitable for famers. The powered raw sample was treated with sodium hydroxide (NaOH) and hydrogen peroxide (H2O2) as followed the design experiment. The use of response surface method is helping researcher to save time and effort but still gain meaningful predicted value that closed to the actual value. The highest total sugar was given when the pretreatment condition is solid to liquid ratio of 0.05, 1% NaOH, 1% H2O2 for 72 h. The efficiency of hydrolysis can reach 47% after 24 h with cellulase enzyme at 50 °C, 150 rpm and highest ethanol concentration was obtained on the fifth day of fermentation.

Sustainability assessment of biogas production from buffalo grass and dung: biogas purification and bio-fertilizer.

Biomass from wetland aquatic grass and buffalo grass can be exploited for biogas production, because this substrate is plenteous and does not compete with food production. In this study, the grass substrate was physically pretreated by boiling with different retention time to increase its biodegradability and was examined in batch mode. Boiling pretreatment suggested that 100 °C with 2 h retention time was the best condition. The results showed that the optimum grass concentration in the 1:1 ratio of co-digestion mixture with manure produced the highest methane yield. The results suggested that co-digestion of buffalo grass and buffalo dung was a promising approach for improving biogas production. This study was achieved the upgraded biogas through biological purification contained 90.42% CH4 8.04% CO2 1.43% O2 and 0.11% other trace gases-a remarkable performance based on an efficiency criteria. Furthermore, the digestate has high nutrient concentrations that can potentially use as fertilizer.