Optimization of the Pretreatment of the Mixture of Cassava Peelings and Pineapple Fibers Using Response Surface Methodology and a Process Simulator for the Bioethanol Production

The increase in oil prices and greenhouse gas emissions has led to the search for substitutes for fossil fuels. In Cameroon, the abundance of lignocellulosic resources is inherent to agricultural activity. Production of bioethanol remains a challenge given the crystallinity of cellulose and the presence of the complex. The pretreatment aimed to solubilize the lignin fraction and to make cellulose more accessible to the hydrolytic enzymes, was done using the organosolv process. A mathematical modeling was performed to point out the effect of the temperature on the kinetics of the release of the reducing sugars during the pretreatment. Two mathematical model was used, SAEMAN’s model and Response surface methodology. The first show that the kinetic parameters of the hydrolysis of the cellulose and reducing sugar are: 0.05089 min-1, 5358.1461 J·mol-1, 1383.03691 min-1, 51577.6100 J·mol-1 respectively. The second model was used. Temperature is the factor having the most positive influence whereas, ethanol concentration is not an essential factor. To release the maximum, an organosolv pre-treatment of this sub-strate should be carried out at 209.08°C for 47.60 min with an ethanol-water ratio of 24.02%. Organosolv pre-treatment is an effective process for delignification of the lignocellulosic structure.

Production of Cellulase and Xylanase by Aspergillus terreus KJ829487 Using Cassava Peels as Subtrates

Cassava (Manihot esculenta, Crantz) is one of the most important food plants in West Africa. Its peels are made up of cellulose, hemicellulose and lignin. This lignocellulolytic biomass can be converted using microbial enzymes to fermentable sugars which have wide range of biotechnological relevance in many fermentation processes. The aim of this study is to screen filamentous fungi from decaying cassava peels that are good producers of xylanases and cellulases. Decaying parts of cassava peels were obtained and brought to the laboratory for further work. Fungi were isolated, identified and screened for cellulase and xylanase production. Isolate with highest frequency of occurrence and enzyme production was identified using phenotypic and molecular method. Optimisation of growth conditions for enzymes production was monitored using the DNSA method, also saccharification of cassava peel were carried out using the enzymes obtained from the isolate. Aspergillus terreus KJ829487 was the predominant fungus. It produces cellulases and xylanases optimally at 40°C, pH 6 and 8, utilising carboxymethylcellulose (CMC) or xylose and yeast extracts as its carbon and nitrogen sources respectively. Saccharification of the peels yielded 584 mg/L glucose, 78 mg/L xylose and 66 mg/L rhamnose. Aspergillus terreus KJ829487 obtained from cassava peels have the ability to produce high concentration cellulases and xylanases which effectively hydrolysed the lignocelluloses’ biomass to fermentable sugars.

The Potential Use of Cassava Peel for Treatment of Mine Water in Mozambique

In the last decade, Mozambique became one of the top coal producers in Africa. The coal mines are in Moatize district in the center of the country, inside the lower Zambezi river basin. Pollution due to mining activities has negative impacts in agriculture, fishing, water supply, and presents risks to public health. Mozambique is one of the largest cassava producers in the world. More than 1.5 million tons of cassava peel are generated in the country and this agro-waste is discarded. The aim of this study is to discuss the possibility of using cassava peel to treat mine water. Cassava peel can be used as carbon sources for sulfate reducing bacteria in bioremediation, as an adsorbent and as a filter medium. An integrated method is proposed for treatment of mine water in Moatize. It was suggested that applying cassava peel generated in developing countries for treatment of mine water could be a good solution to protect the environment against mining pollution.

Evaluating the Stability of Indigenous Akwadum Soil with Cassava Peel Ash and Quarry Dust

Cassava peels are produced as a waste from cassava, which are disposed into landfills. These become an environmental problem;therefore the use of cassava peel ash (CPA) as a soil stabilizer must be encouraged. This study investigates the effects of CPA and quarry dust (QD) on the engineering properties of Akwadum soil behavior, using compaction test, Atterberg limit, and California bearing ratio (CBR). These properties were compared with those of unstabilized soil (original) and soil stabilized with CPA and QD. The natural soil was obtained from a borrowed pit at Akwadum near Koforidua at an average depth of 0.8 m which is meant for road works. This soil sample was stabilized with CPA and QD at 5%, 10% and 20% respectively. The compaction, California bearing ratio and Atterberg limit test were performed on the stabilized soils to thoroughly evaluate them. The results indicate that increasing the percentage of CPA to the natural soil decreases the maximum dry density at increasing optimum water content. The addition of QD at higher percentage increases the maximum dry density at decreasing optimum water content. The results reveal that both QD and CPA improve the engineering properties of the soil with QD providing better results.

Co-pyrolysis of cassava peel with synthetic polymers:thermal and kinetic behaviors

This research effort focuses on the co-pyrolysis of cassava peels waste and some synthetic polymers towards energy conversion and reducing the volume of these waste fractions dumped on dumpsites.The co-pyrolysis behavior and pyrolysis kinetics of various synthetic polymer wastes/cassava peel blends were investigated by blending cassava peel waste with low-density polyethylene(LDPE),polyethylene terephthalate(PET),and polystyrene(PS)at different weight ratios.The physical characteristics of each sample were investigated and the co-pyrolysis experiments were conducted at a heating rate of 10℃/min from room temperature to 800℃in N_(2)atmosphere in a thermogravimetric analyzer.Subsequent to thermal decomposition,kinetic analysis was done using the thermogravimetric data.Results from physicochemical characterization showed that cassava peel has a relatively lower calorific value of 15.92 MJ/kg compared with polystyrene(41.1 MJ/kg),low-density polyethylene(42.6 MJ/kg),and polyethylene terephthalate(21.1 MJ/kg).The thermal decomposition behavior of cassava peel was seen to be significantly different from those of the synthetic polymers.The decomposition of the biomass material such as cassava peel generally occurs in two stages while the decomposition of LDPE,PS,and PET occurred in a single stage.The activation energy required for thermal degradation in cassava peel was also found to be lower to that of the plastic material.The co-pyrolysis of cassava peel and different synthetic polymers affected the thermal and kinetic behaviors of the blends,reduce the activation energy and residue after pyrolysis.

Synthesis and characterization of starch nanoparticles from cassava Pee

Starch nanoparticles are used as a matrix with natural rubber for tire making, alternative adsorbents for wastewater treatment, drug carriers, packaging materials, emulsion stabilizers and fat replacers. The objective of this study is to prepare the starch nanoparticles from cassava peel by mineral acid hydrolysis using hydrochloric and sulfuric acids and perform the characterization of starch nanoparticles with Fourier transform infrared (FTIR),X-ray diffraction (XRD) and scanning electron microscope (SEM)It was found that the obtained yield of starch nanoparticles by H2SO4was higher than that by HCl.

Optimization and kinetics of glucose production via enzymatic hydrolysis of mixed peels

The optimization and kinetics of glucose production via enzymatic hydrolysis of mixed peels were carried out.The substrate was characterized using proximate analysis and hydrolysis.The process was optimized using response surface methodology while the kinetics of the hydrolysis was studied using Michealis-menten model.The results obtained showed that the mixed peels have high hemicellulose content,hydrolysable carbohydrate and cellulose.The optimum conditions for glucose yield of 79%by enzymatic hydrolysis are temperature of 36℃,time of five days,pH of 4.55 and enzyme dosage of 0.428 g/50 mL.Enzymatic hydrolysis obeyed Michealis-Menten kinetic model with spontaneous and feasible reactions.Therefore,the results have proved that mixed peels(cassava and potato peels)is a good substrate for glucose production and study of other waste peels as feed-stock is recommended.