Biochemical Engineering

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Browsing Biochemical Engineering by Author "Eduardo, Ojito (Prof.)"

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    Investigation on Mineral Characterization of Powder Injera
    (Addis Ababa University, 2019-10) Mulatu, Betsegaw; Eduardo, Ojito (Prof.)
    Injera is a fermented, sour bread consumed as a staple food in Ethiopia and Eritrea. The bread can be prepared from various cereals but tef [Eragrostis tef (Zucc.) Trotter] is the most preferred ingredient. A deep study on its inherent characteristics related to processing of injera is needed for its use in various food applications. This research attempt to use spray dryer technology to cook injera, as an alternative method of injera processing. And the product is forwarded for the use of as a food supplement. Also the researcher study the impact of type of tef white and red on nutritional composition of powder injera and impact of fermentation time at 24h, 48h, and 72h on moisture content, ash content, fiber content, iron content, zinc content, calcium content, potassium and sodium content of nutritional composition of powder injera was tested using statistic and regression analysis. Microsoft excel and two factorial three level design expert 11 is used to analyze the experimental result. It is observed that red tef has higher calcium, zinc, and iron value than the white tef but the white tef powder injera has sodium and potassium content than the red tef powder injera. And it is observed that at fermentation time of 48h the powder injera has higher mineral content than at fermentation time of 24h and 72h.
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    Production of Bioethanol from Brewery Spent Grain Using Cellulase Enzyme Hydrolysis
    (Addis Ababa University, 2018-07) Emru, Yidnekew; Eduardo, Ojito (Prof.)
    Bioethanol is a clear, colorless and mobile flammable liquid chemical compound with acceptable odour, and produced from biomass feed stocks through fermentation. The objective of this study was production of bioethanol from Barley spent grain by using cellulase enzyme hydrolysis. Decreasing of world petroleum reserves, fluctuation of petroleum price and environmental concerns, low yield cellulose acid hydrolysis and formation of inhibitory were the problem statement. Enzymatic hydrolysis method was used for cellulose hydrolysis, producing monomeric C6 sugars (glucose); enzymatic hydrolysis is more specific and high conversion rates can be achieved in long reaction times obtaining very high yields. Raw material characterization of BSG were, hemicelluloses content 28.4 %, cellulose content 27 %, and dry matter content 98.2 %. The aim of pretreatment is to disrupt recalcitrant structures of cellulosic biomass to make cellulose more accessible to the enzymes that convert carbohydrate polymers into fermentable sugars. The pretreated feedstock was mixed with 1.25 % (v/v) sulfuric acid solutions with a liquid-to-solid ratio of 20 %( w/w) and it was occurred on the temperature 121 ºC and time of 17 min, the severity factor coefficient was 0.198. Cellulase enzyme was produced from BSG using bacillus subtilus, under liquid state fermentation for 5 days at temperature of 37 ºC with pH of 5.0, in controlled incubator. For the enzyme hydrolysis, 26 full factorial central composite design (CCD) was applied to investigate the effect of temperature (40-50 ºC), pH (4.0-5.0), reaction time (24-72 hr.) and enzyme loading (1-2 %) using Design expert® 6 software. RSM was applied to investigate the interaction effect of hydrolysis process variables on the yield of ethanol from BSG. After hydrolysis process sugar content of the hydrolysate was quantified using spectrophotometer measuring its absorbance. Fermentation of the hydrolysate were performed 2.5 % Saccharomyces cerevisiae and 2.5 % fusarium oxysporum at 30 ºC temperature, pH 5.0 and 72 hr. fermentation time for all samples. Significance of the process variables were analyzed using analysis of variance. As the result of RSM optimization, the best yield of TRS was found at 40 ºC hydrolysis temperature, 4.5 PH, 48 hr. reaction time and 1.5 % v/v enzyme loading. Under these condition 96.55 %w/w and 53.68 % per 6.58 g dry barley spent grain of TRS and bio-ethanol respectively obtained.
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    Utilization of Duckweed as a Carbon Source for the Production of Lactic Acid
    (AAU, 2017-06) Endriss, Ali; Eduardo, Ojito (Prof.)
    Despite a great deal of research work on lactic acid fermentation in the past, the production of lactic acid from duckweed has yet to be investigated. In this study lactic acid was produced from duckweed thourgh existing technologies of saccharification/acid hydrolysis and fermentation of starch would been used for duckweed-to-lactic acid conversion. For this purpose, small fronds of duckweed plants was harvested, crushed and prepared into a solution. The duckweed slurry was subjected to acid hydrolysis. Then, fermentation of duckweed hydro-lysate was done in shake flasks using Lactobacillus plantarum species which was isolated from enset. The immediate solutions were anlysed by using UV-Spectrophotometer (concentration of lactic acid) and serial dilution methocd (viable cell count). Finally, the optimum operation conditions of fermentation (i.e. incubation time, pH and temperature) were determined by using design expert software (version 10.0.1). and the optimum incubation time, pH and temprature were 21 hours, 6.4 and 34 0 C respectively. The amount of lactic acid produced and number of viable cells at optimum operating conditions of fermentations were 15.6574g/L and 4.34004E+008.