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Food waste generation has increased in recent years due to population growth. The continuous rise in food production for human consumption has resulted in 1.3 billion tons of food waste annually worldwide. Waste bread, an inexpensive substrate with high carbohydrate content, can hydrolyze by proper methods, such as enzymatic hydrolysis, for utilization in fermentation. Glutamic acid, a non-essential amino acid with various applications in pharmaceuticals, food industries, and cosmetics, can be produced by fermentation. In this study, we applied waste bread, as a cost-effective starchy waste, to produce fermentable substances through enzymatic hydrolysis. This process resulted in a significant increase in reducing sugar concentration from 1.285 ± 0.195 g/L to 123.282 ± 0.924 g/L. The obtained hydrolysate was utilized as a carbonic source for the glutamic acid synthesis by Corynebacterium glutamicum PTCC 1532. To enhance the glutamic acid yield, response surface methodology was employed to optimize the independent variables. The optimum levels of reducing sugar concentration of hydrolysate, urea concentration, biotin concentration, and inoculum size was 49.889 g/L, 6.812 g/L, 6.57 μg/L, and 5.339% (v/v), respectively. Under these optimized conditions, the experimental glutamic acid production was 21.34 ± 0.204 g/L, which demonstrated a reasonable correlation between the predicted and experimental results. This study illustrated that waste bread can serve as a low-cost carbon source for producing valuable compounds such as glutamic acid. [ABSTRACT FROM AUTHOR]

Algerians are among the largest consumers of bread throughout the year and produce large amounts of bread waste. As bread is made from imported wheat, these losses on currency are a heavy loss for the national economy. To minimize these losses, Algeria needs to encourage the recycling of stale bread to minimize the cost of importing soft wheat and valorize it for farmers. This paper presents a framework based on the Internet of Things (IoT) to monitor and collect waste bread from recycling bins. This system could assist Small and Medium Enterprises (SMEs) in Algeria in bread waste collection, by monitoring the level of filling of the outdoor waste bins. The proposed system's architecture used a Mega 2560 microcontroller, HC-SR04 ultrasonic sensors, and SIM 808/900 modules. [ABSTRACT FROM AUTHOR]

A recent trend in sustainable bioethanol production is the use of agricultural waste or food waste as an inexpensive and the most available feedstock. Bread waste is the major food waste that could be successfully used for the production of bioethanol. The aim of this study was to optimize ethanol production by the response surface methodology (RSM) using waste bread hydrolysate. Waste bread hydrolysate was obtained using crude hydrolytic enzymes that produce bacterial isolate Hymenobacter sp. CKS3. The influence of time of fermentation (24–72 h) and waste brewer’s yeast inoculum (1–4 %) on ethanol production was studied. The optimal conditions, obtained by central composite design (CCD), were 48.6 h of fermentation and 2.85 % of inoculum. Under these conditions, a maximum of 2.06 % of ethanol concentration was reached. The obtained ethanol concentration was in good correlation, coefficient of 0.858, with yeast cell yield. The results obtained in this study imply that waste bread hydrolysate could be used as a biomass source for biofuel production with multiple benefits relating to environmental protection, reduction of production costs, and saving fossil fuels.

Microbial hydrolytic enzymes are relevant biotechnological products that can be applied in various industries. In this study, we have tested the activity of hydrolytic enzymes of a newly isolated Hymenobacter sp. CKS3 strain and showed, for the first time, that members of Hymenobacter genus have still unexplored hydrolytic potential. Crude hydrolytic enzymes, produced by the strain CKS3 on a waste medium, were incorporated into a process of bioethanol production using waste bread. The conditions for bread hydrolysis were optimized using statistical design. Waste bread hydrolysate obtained under optimal conditions (100.73 h of hydrolysis, waste bread concentration 20.36% and agitation speed 200 rpm) contained 19.89 g/l of reducing sugars. A high performance liquid chromatography of hydrolyzed waste bread samples showed that the main components of the hydrolysate were dextrins, maltotriose, maltose and glucose. When using this substrate and waste baker's yeast for ethanol production under non-optimized conditions 1.73% of ethanol was produced. The results of this study showed that a newly isolated Hymenobacter sp. CKS3 can be utilized for enzymatic hydrolysis and bioethanol production in a process relying on waste materials. Furthermore, it was demonstrated that members of Hymenobacter genus have a significant and currently unexplored potential for bio-based industrial applications. Image 1 • First report of Hymenobacter enzymatic potential for waste bread hydrolysis. • Production of enzymes by novel red pigment bacterial strain Hymenobacter sp. CKS3. • An optimal design was used for optimize enzymatic hydrolysis of waste bread. • 19.89 g/l of reducing sugars was released from waste bread by CKS3 crude amylase. • The optimized waste bread hydrolysate was used for ethanol production. [ABSTRACT FROM AUTHOR]

Technological properties of aqueous solutions of xanthan gums produced by various Xanthomonas species using waste bread (WB) hydrolyzate as a carbon source to reduce the overall product cost and to utilize waste bread were investigated and compared with commercial xanthan gum. While the highest water holding capacity was detected in the commercial xanthan gum, oil holding capacity was higher in xanthan gums from X. campestris DSM 19000 and X. axonopodis pv. begoniae than commercial gum. Pudding samples were prepared by the gums obtained and Ostwald de Waele model was successfully described the flow behavior. The highest consistency coefficient (K) value were obtained by the sample without gum addition as 161.2 Pa.sn, this was followed by the sample with the gum from X. axonopodis pv.begoniae with 139.3 Pa.sn and X. hortorum pv.pelargonii with 133.2 Pa.sn . Flow behavior index (n) values varied between 0.12 and 0.49 and increased with the addition of the gum. Therefore, this study showed that the pudding samples prepared with the gums from X. axonopodis pv. begoniae and X. hortorum pv. pelargonii isolates using waste bread as substrate were found to be more resistant to shear rate and had a more robust gel structure. [ABSTRACT FROM AUTHOR]

Activated carbon foam was prepared via direct pyrolysis of waste bread (WB) under CO2 atmosphere. The product was characterized by N2 adsorption/desorption and Fourier transform infrared spectroscopy (FTIR). The preparation process was investigated online by a thermogravimetric analyzer coupled with FTIR (TG-FTIR). The adsorption isotherms of methylene blue (MB) by the product were investigated. The experimental data demonstrated that the product had a high surface area of 1575 m2 g−1 and a total pore volume of 0.883 cm3 g−1. Thermal decomposition of polymers in WB mainly occurred between 200 and 500 °C, leading to the release of carbonyl compounds, aliphatic hydrocarbons, alcohols, and furans. The dominant CO2 activation process started at above 800 °C. The MB adsorption equilibrium data followed Langmuir model with a monolayer adsorption capacity of 403 mg g−1. This study provides a reference for the utilization of WB as a promising precursor of activated carbon foam adsorbent, which has highly porous structure and excellent floatability in water. [ABSTRACT FROM AUTHOR]

Bacillus subtilis, an alkaline protease producing strain isolated from soil sample, was identified by 16S rRNA gene sequencing method and its biochemical properties. The optimum pH and temperature of the enzyme were found as 9.5 and 60°C, respectively. The enzyme showed excellent stability with some commercial liquid laundry detergents. Wash performance analysis revealed that B. subtilis crude protease could effectively remove bloodstains. Bacillus subtilis strain produced nine major extracellular proteases, which was revealed by zymography technique. Appraising its promising properties, Bacillus subtilis crude enzyme can be considered as a potential candidate for future use in detergent industries. [ABSTRACT FROM AUTHOR]

Abstract Waste bread hydrolysate was used as a biosource for xanthan production by various isolates and standard bacteria (Xanthomonas campestris DSM 19000). Influence of operational conditions used in the process of xanthan production were evaluated through yield of xanthan, rheological properties of aqueous solution and fermentation kinetics. For the highest yield and viscosity, optimum conditions including carbon source concentration, inoculum volume and agitation rate were determined for 4 different strains by using response surface methodology. The highest gum yield as 14.3 g/L was obtained by Xanthomonas axonopodis vesicatoria and the highest conversion rate of waste bread to xanthan gum was found as %14.1 for Xanthomonas hortorum pv. pelargonii. Whereas, the highest aqueous solution viscosity of gum produced from standard bacteria was 11.2 Pa.sn at glucose ratio of 4%, inoculum volume of 5% and mixing rate of 225 rpm. For fermentation kinetics; the values of growth associated parameters revealed that they are mostly affected by the rate of xanthan gum production and substrate consumption. In general, optimum conditions to obtain the highest xanthan gum yield were different from that to achieve the highest viscosity. This study shows the potential of waste bread hydrolyzates as the promising economic carbon source for xanthan gum production. Graphical abstract Image 1 Highlights • Highest xanthan gum yield (14.3 g/L) was obtained by X. axonopodis vesicatoria from waste bread. • 14.1 g of xanthan gum can be obtained from 100 g waste bread. • X. campestris DSM 19000 produced gum with the highest viscosity. • Cell growth of microorganisms depended on xanthan gum production and substrate consumption. [ABSTRACT FROM AUTHOR]

Finding of optimal hydrolysis conditions is important for increasing the yield of saccharides. The higher yield of saccharides is usable for increase of the following fermentation effectivity. In this study optimal conditions (pH and temperature) for amylolytic enzymes were searched. As raw material was used waste bread. Two analytical methods for analysis were used. Efficiency and process of hydrolysis was analysed spectrophotometrically by Somogyi-Nelson method. Final yields of glucose were analysed by HPLC. As raw material was used waste bread from local cafe. Waste bread was pretreated by grinding into small particles. Hydrolysis was performed in 100 mL of 15 % (w/v) waste bread particles in the form of water suspension. Waste bread was hydrolysed by two commercial enzymes. For the liquefaction was used α‑amylase (BAN 240 L). The saccharification was performed by glucoamylase (AMG 300 L). Optimal conditions for α‑amylase (pH 6; 80 °C) were found. The yield of total sugars was 67.08 g∙L-1 (calculated to maltose). As optimal conditions for glucoamylase (pH 4.2; 60 °C) were found. Amount of glucose was 70.28 g∙L1. The time of waste bread liquefaction was 180 minutes. The time of saccharification was 90 minutes. The results were presented at the conference CECE Junior 2014.

[Display omitted] • 5-Hydroxymethyl-2-furanamine was prepared from bread waste via chemoenzymatic way. • Betaine:malonic acid (18%) catalyzed bread waste (40 g/L) to HMF (30.3% yield). • HNILGD-AlaDH cell expressed L -alanine dehydrogenase and ω-transaminase mutant HNILGD. • Bioamination of HMF was conducted with a low dose of amine donor (D- Ala/5-HMF = 2/1). • The yield was 0.28 g 5-hydroxymethyl-2-furanamine/(g bread waste). In this study, efficient and sustainable conversion of waste bread (WB) to 5-hydroxymethyl-2-furoamine (HMFA) was achieved in a cascade reaction in betaine:malonic acid (B:MA) − water. 5-HMF (30.3 wt% yield) was synthesized from WB (40.0 g/L) in B:MA − water (B:MA, 18 wt%) in 45 min at 190 °C. By using the newly created recombinant E. coli HNILGD-AlaDH cells expressing L -alanine dehydrogenase (AlaDH) and ω-transaminase mutant HNILGD as biocatalyst, the WB-valorized 5-HMF was biologically aminated into HMFA in a high yield (92.1%) at 35 °C for 12 h through in situ removal of the amino transfer by-products of the amine donor, greatly reducing amine donor dosage (from D- Ala/5-HMF = 16/1 to D- Ala/5-HMF = 2/1, mol/mol) and improving the productivity of HMFA (0.282 g HMFA per g WB). This two-step chemical-enzymatic cascade reaction strategy with B:MA and HNILGD-AlaDH whole-cell provides a new idea for the chemoenzymatic synthesis of valuable furan chemicals from waste biomass. [ABSTRACT FROM AUTHOR]

Background: Many species of sustainable mycotoxin-producing fungi are considered as dangerous agents for humans. Bread is one of the materials exposed to fungal infection and molds are amongst the most important pollutant microbial and chemical mycotoxin-producing agents of bread. In this study, the microbial and chemical contamination of recycled waste breads and the types of produced mycotoxins at two areas of Tehran municipality, Iran, were investigated. Methods: Using fungal culture media, twenty samples of waste bread were analyzed for microbial contaminations. To recognize contamination to mycotoxins, high-performance liquid chromatography (HPLC) method and fuorescence detector (FLD) were used. Findings: All but one sample were contaminated to mold infections such as Aspergillus, Penicillium, and yeasts including Geotricum candidum, Candidia albicans and Saccharomyces cerevisiae. Eight samples were contaminated to aflatoxins, ochratoxin A and deoxynivalenol, whereas none of them showed contamination with zearalenone. Conclusion: The results indicated that presence of microbial and toxic contamination in bread waste is inevitable, which is harmful for human health. The sanitary control of food waste to reduce or eliminate microbial hazards in food recycling is necessary.

In this paper yields of bioethanol from seven samples of bread were compared. Samples of bread were produced and prepared in a laboratory by mixing wheat and buckwheat flour in amounts of 0, 20, 40, 50, 60, 80 and 100%. At first, the analysis of all seven samples of bread was done (dry matter, starch content and pH value of bread sample suspensions). Then the waste bread suspensions were hydrolyzed by applying commercial hydrolytic enzymes, Termamyl® SC and SAN Extra® L. The fermentation process was carried out with dry instant yeast, Saccharomyces cerevisiae, after which distillation of all fermented suspensions was performed. The ethanol contents in the distillates of all seven samples were determined. The highest yield of bioethanol was detected in the bread sample made of pure wheat flour. The ethanol yield gradually decreased with increasing content of buckwheat flour in bread. These results could be useful when considering the possibility of utilization of waste bread from different sources as a feedstock for bioe­thanol production.

Biosurfactants are amphiphilic biological compounds which are produced by various fungi and bacteria that reduce surface and interfacial tensions. In this study, a biosurfactant-producing microorganism was isolated from a soil sample which was collected from Cukurova University campus. The microorganism was identified as Bacillus subtilis by 16 S rRNA gene sequencing method and by investigating its biochemical properties obtained from VITEK-II Compact Identification System. Production of the biosurfactant was carried out by Bacillus subtilis using waste bread as substrate in culture medium. The biosurfactant production process was followed by surface tension measurement, emulsification index assay, determination of carbohydrate groups, foam stability and antimicrobial and antifungal activity observation of biosurfactant. Bacilllus subtilis showed very good hemolytic activity and diameter of the hemolytic zone was observed to be larger than 3 cm i.e. complete hemolysis (++++). Xylen was the best substrates for emulsification index (39%) of biosurfactant produced from Bacillus subtilis. Surface tension of biosurfactant was determined as 48.64 mN/m by using pendant drop method. The rhamnose test was positive which indicates that biosurfactant could be of rhamnolipid type. Biosurfactant had a good foaming stability and the purified biosurfactant exhibited antimicrobial and antifungal activities. Consequently, biosurfactant produced by Bacillus subtilis will provide improved wash efficiency as a detergent additive due to its characteristic features. [ABSTRACT FROM AUTHOR]

[Display omitted] • 2,5-Diformylfuran (DFF) was prepared from biobased substrates in [BA][LA]–H 2 O. • Bread waste (50 g/L) was catalyzed to HMF (33% yield) in [BA][LA]–H 2 O. • Fructose (18 g/L) was catalyzed to HMF (92% yield) in [BA][LA]–H 2 O. • The prepared HMF was biologically oxidized to DFF by E. coli pRSFDuet-GOase. • Bread waste and fructose were efficiently catalyzed to DFF. 2,5-Diformylfuran, which can be prepared via the oxidation of biobased HMF, has received considerable attention because of its potential applications in producing furan-based chemicals and functional materials, such as biofuels, polymers, fluorescent material, vitrimers, surfactants, antifungal agents and medicines. This work aimed to develop an efficient one-pot process for chemoenzymatic transformation of biobased substrate to 2,5-diformylfuran with deep eutectic solvent (DES) Betaine:Lactic acid ([BA][LA]) catalyst and oxidase biocatalyst in [BA][LA]–H 2 O. Using waste bread (50 g/L) and D -fructose (18.0 g/L) as feedstocks in [BA][LA]–H 2 O (15:85, vol/vol), the yields of HMF were 32.8% (15 min) and 91.6% (90 min) at 150 °C, respectively. These prepared HMF could be biologically oxidized to 2,5-diformylfuran by Escherichia coli pRSFDuet-GOase, achieving a productivity of 0.631 g 2,5-diformylfuran/(g fructose) and 0.323 g 2,5-diformylfuran/(g bread) after 6 h under the mild performance condition. This bioresourced intermediate 2,5-diformylfuran was effectively synthesized from biobased feedstock in an environmentally-friendly system. [ABSTRACT FROM AUTHOR]

Simultaneous dark fermentative hydrogen and ethanol production from waste bread in a mixed packed tank reactor (MPTR) was investigated. Waste bread was first hydrolyzed by the produced enzymes to generate the waste bread hydrolysate which was subsequently introduced to the MPTR for dark fermentative hydrogen and ethanol production. The optimal hydrogen and ethanol production rates were 15.01 mmol/(h·L) and 23.25 mmol/(h·L) when the organic loading rate reached 32 g/(L·d). The unit hydrogen and ethanol production were 4.87 mmol hydrogen/g waste bread and 7.54 mmol ethanol/g waste bread, respectively. This study provided a new direction for economic and efficient hydrogen and ethanol production from waste bread. [ABSTRACT FROM AUTHOR]

Finding of optimal hydrolysis conditions is important for increasing the yield of saccharides. The higher yield of saccharides is usable for increase of the following fermentation effectivity. In this study optimal conditions (pH and temperature) for amylolytic enzymes were searched. As raw material was used waste bread. Two analytical methods for analysis were used. Efficiency and process of hydrolysis was analysed spectrophotometrically by Somogyi-Nelson method. Final yields of glucose were analysed by HPLC. As raw material was used waste bread from local cafe. Waste bread was pretreated by grinding into small particles. Hydrolysis was performed in 100 mL of 15 % (w/v) waste bread particles in the form of water suspension. Waste bread was hydrolysed by two commercial enzymes. For the liquefaction was used α-amylase (BAN 240 L). The saccharification was performed by glucoamylase (AMG 300 L). Optimal conditions for α-amylase (pH 6; 80 °C) were found. The yield of total sugars was 67.08 g∙L-1 (calculated to maltose). As optimal conditions for glucoamylase (pH 4.2; 60 °C) were found. Amount of glucose was 70.28 g∙L1. The time of waste bread liquefaction was 180 minutes. The time of saccharification was 90 minutes. The results were presented at the conference CECE Junior 2014. [ABSTRACT FROM AUTHOR]

Biohydrogen production from waste bread in a continuous stirred tank reactor (CSTR) was techno-economically assessed. The treating capacity of the H 2 -producing plant was assumed to be 2 ton waste bread per day with lifetime of 10 years. Aspen Plus was used to simulate the mass and energy balance of the plant. The total capital investment (TCI), total annual production cost (TAPC) and annual revenue of the plant were USD931020, USD299746/year and USD639920/year, respectively. The unit hydrogen production cost was USD1.34/m 3 H 2 (or USD14.89/kg H 2 ). The payback period and net present value (NPV) of the plant were 4.8 years and USD1266654, respectively. Hydrogen price and operators cost were the most important variables on the NPV. It was concluded that biohydrogen production from waste bread in the CSTR was feasible for practical application. [ABSTRACT FROM AUTHOR]

In this study, continuous biohydrogen production from waste bread by anaerobic sludge was performed. The waste bread was first hydrolyzed by the crude enzymes which were generated by Aspergillus awamori and Aspergillus oryzae via solid-state fermentation. It was observed that 49.78 g/L glucose and 284.12 mg/L free amino nitrogen could be produced with waste bread mass ratio of 15% (w/v). The waste bread hydrolysate was then used for biohydrogen production by anaerobic sludge in a continuous stirred tank reactor (CSTR). The optimal hydrogen production rate of 7.4 L/(Ld) was achieved at chemical oxygen demand (COD) of 6000 mg/L. According to the results obtained from this study, 1 g waste bread could generate 0.332 g glucose which could be further utilized to produce 109.5 mL hydrogen. This is the first study which reports continuous biohydrogen production from waste bread by anaerobic sludge. [ABSTRACT FROM AUTHOR]

The aim of this study was to optimise airflow rate for glucoamylase and protease production from waste bread via solid state fermentation by Aspergillus awamori in packed bed bioreactors. Airflow rates, between 0.40 and 3.00 vvm, were tested. In all experiments, the fungal growth was almost uniform throughout the solids. Fungi grew both on and within the substrate and fungal cakes were formed. The highest glucoamylase and protease activities were recorded as 130.8 U/g bread (db) and 80.3 U/g bread (db) in the experiments with 1.50 wm airflow rate, respectively. These values are 27.2% and 32.3% higher than the glucoamylase and protease activities obtained in petri dish experiments with static air. At 1.50 vvm airflow rate, the dry weight of the solids had decreased to 46% of the initial value at the end of the fermentation. The temperature of the solids increased up to 37.5 °C with high axial temperature gradients due to high metabolic activity. The average moisture content of the solids first decreased to 150% (db) and then increased to 275% (db) by the end of the fermentation. Both above and below 1.50 wm airflow rate, enzyme production and fungal growth were affected significantly. Also, a Gaussian-based mathematical model was developed to model the effects of airflow rate on enzyme production. The model fitted almost seamlessly to the experimental data. Thus, this study clearly showed the effects of aeration on glucoamylase and protease production from waste bread under solid state fermentations. [ABSTRACT FROM AUTHOR]

The subject of this research project was assessment of direct starch to ethanol conversion process course of waste wheat-rye bread using granular starch hydrolyzing enzyme (GSHE). Several pretreatment methods (enzymatic prehydrolysis, microwave irradiation, sonification) were used to improve the course of fermentation and were compared with separate hydrolysis and fermentation (SHF). Due to high water binding capacity of raw material fermentations were conducted at a substrate loading of 150 g kg-1. Only during enzymatic pretreatment and the SHF process the raw material was preliminary liquefied so its higher concentrations could be applied. The dynamics of fermentation was similar in all studied variants. The fermentation of unpretreated waste bread ended with 80.00% ethanol yield (354.36 g kg-1 of raw material). Pretreatment of raw material improved ethanol yield by ca. 3-8%. [ABSTRACT FROM AUTHOR]

The article focuses on the nutritional value of conventional urea molasses multinutrient block (UMMB) with agro-industrial wastes such as tomato pomace (TP), sundried waste bread (WB), and spent sugar syrup (SSP) in buffaloes. Topics highlighted include rumen metabolites, methods of gathering the non-conventional supplements used in the study, and the chemical properties of feeds.

Highlights: [•] Waste bread recuperation for the production of value added products. [•] Solid state fermentation of waste bread by Aspergillus awamori. [•] Kinetic analysis of the multi-enzyme solution from waste bread. [•] Half-life of glucoamylase from waste bread is much higher than that from wheat flour. [ABSTRACT FROM AUTHOR]

When it is not consumed, bread presents a major source of food waste, both in terms of the amount and its economic value. However, bread also possesses the characteristics of an ideal substrate for solid state fermentation. Yet nearly all wasted bread ends up in landfill sites, where it is converted into methane by anaerobic digestion. Governments are finally taking action and, according to the EU Landfill Directive, for example, biodegradable municipal waste disposed into landfills must be decreased to 35% of 1995 levels, by 2020. Solid state fermentation of waste bread for the production of value added products is a novel idea, which could help with the achievement of this target. In this study, glucoamylase and protease production from waste bread pieces, via solid state fermentation, was investigated in detail. The optimum fermentation conditions for enzyme production were evaluated as, 20 mm particle size, 1.8 (w/w, db) initial moisture ratio, and duration of 144h. Under these conditions, glucoamylase and protease activities reached up to 114.0 and 83.2 U/g bread (db), respectively. This study confirms that waste bread could be successfully utilised as a primary raw material in cereal based biorefineries. [ABSTRACT FROM AUTHOR]

In this study, the operation of a single cylinder, four stroke, SI engine powered by fuels created by blending two different bioethanol with gasoline was evaluated on the basis of energy and exergy analyses. Within the scope of the study, test engine was tested by operating it with fuel blends, prepared by adding both bioethanol, one of them was produced from waste bread and the other, originating from sugar beet, was supplied, to gasoline at different rates by of 5, 10, 15, 85 and 100% under five different engine loads at maximum torque speed, 2500 rpm. The variation of energy and exergy parameters was examined by comparing the blends, prepared to have similar volumetric content, each other and by comparing all with gasoline. As a result of the study, it was determined that the addition of bioethanol had generally decreasing effect on energy loss rate, exergy loss rate and exergy destruction rate. For fuel blends containing low levels of bioethanol, variation of ethanol has created little differences on all energy and exergy parameters but bioethanol type clearly showed its effect when bioethanol rate increased to 85% and 100%. Although waste bread bioethanol could not catch sugar beet bioethanol in terms of thermal efficiency (14.4% for E100b and 16.4% for E100 as load average) and exergetic efficiency (12.9% for E100b and 14.7% for E100 as load average), both bioethanol have been found to improve both thermal efficiency (12.2% for E0) and exergetic efficiency (11.4% for E0) than that of gasoline. [ABSTRACT FROM AUTHOR]

In this study, bioethanol produced from waste bread by fermentation was evaluated as engine fuel comparing with sugar beet bioethanol purchased. Comparison criteria are parameters of combustion analyses, engine performance and exhaust emissions. Therefore, the experiments were carried out in a single cylinder, four stroke, air cooled SI engine fueled with both bioethanol blended with gasoline in different proportions for different test conditions created with different engine load and a constant engine speed. Whether formed with sugar beet or waste bread bioethanol, fuel blends with similar volumetric contents have similar trends in every sense and their position they take relative to pure gasoline is similar. But when the ones with similar content are compared with each other, the differences emerge. These can be summarized as follows: It has been determined that combustion occurs in a shorter time with lower maximum cylinder pressures and maximum heat release rate if the engine runs with fuels containing waste bread bioethanol. In the case of adding waste bread bioethanol, there was a gradual increase in brake specific fuel consumption and a gradual decrease in thermal efficiency compared to sugar beet added fuels. The use of waste bread bioethanol blended with gasoline has seriously positive results in many emissions aspects such that it has less CO up to 70.9%, less HC up to 34.9% and less NOx up to 5.1%, except for the fact that it has more CO 2 up to 3.5%. [ABSTRACT FROM AUTHOR]