Scholarly article on topic 'Evaluation of Agro-industrial Wastes to Produce Bioethanol: Case Study - Mango (Mangifera Indica L.)'

Evaluation of Agro-industrial Wastes to Produce Bioethanol: Case Study - Mango (Mangifera Indica L.) Academic research paper on "Materials engineering"

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{"S. cerevisiae Y2034" / "Mango (Mangifera indica L.)" / fermentation / bioethanol.}

Abstract of research paper on Materials engineering, author of scientific article — Santis Espinosa L. Fernando, Y. Peréz-Sariñana Bianca, Saldaña-Trinidad Sergio, D. Eapen, P.J. Sebastian

Abstract This study was carried out to evaluate the fermentation performance and behavior of the yeast Saccharomyces cerevisiae Y2034 in mango pulp and peel (Mangifera indica L.). In this paper we studied the fermentation of mango (pulp and peel) a fruit rich in Mexico with high sugar content. The process for producing ethanol comprised the following steps: substrate preparation, preparation of the YPD medium, growth of the yeast S. cerevisiae Y2034, alcohol fermentation and distillation. In this study we utilized the raw materials amounting 75 percent pulp and 25 percent peels and seeds. The maximum growth of yeast was observed in the treatment of pulp and peel with 150g/L of initial reducing sugar, obtaining 2.6×108 cfu mL−1. All the experiments were carried out in triplicate.

Academic research paper on topic "Evaluation of Agro-industrial Wastes to Produce Bioethanol: Case Study - Mango (Mangifera Indica L.)"

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Energy Procedía 57 (2014) 860 - 866

2013 ISES Solar World Congress

Evaluation of agro-industrial wastes to produce bioethanol: case study - mango (Mangifera indica L.)

Santis Espinosa L. Fernandoa*, Peréz-Sariñana Bianca Ya., Saldaña-Trinidad Sergiob, D. Eapenc, P.J. Sebastiana*

a Instituto de Energías Renovables UNAM, Privada Xochicalco s/n CP 62580 Temixco, Morelos, México. bUniversidad Politécnica de Chiapas, calle Eduardo J. Selvas s/n Col. Magisterial. CP 29010 Tuxtla Gutiérrez, Chiapas, México. cInstituto de Biotecnología-UNAM, Av. Universidad 2001, Cuernavaca, Morelos, 62210, México.

Abstract

This study was carried out to evaluate the fermentation performance and behavior of the yeast Saccharomyces cerevisiae Y2034 in mango pulp and peel (Mangifera indica L.). In this paper we studied the fermentation of mango (pulp and peel) a fruit rich in Mexico with high sugar content. The process for producing ethanol comprised the following steps: substrate preparation, preparation of the YPD medium, growth of the yeast S. cerevisiae Y2034, alcohol fermentation and distillation. In this study we utilized the raw materials amounting 75 percent pulp and 25 percent peels and seeds. The maximum growth of yeast was observed in the treatment of pulp and peel with 150 g/L of initial reducing sugar, obtaining 2.6* 108 cfu mL-1. All the experiments were carried out in triplicate.

©2014 TheAuthors.PublishedbyElsevier Ltd.Thisis anopen access article under the CC BY-NC-ND license

(http://creativecommons.Org/licenses/by-nc-nd/3.0/).

Selection and/or peer-review under responsibility of ISES.

Keywords: S. cerevisiae Y2034; Mango (Mangifera indica L.); fermentation; bioethanol.

* Corresponding authors. Tel.: +52 961 190 9340, +52 777 3620090 E-mail address: lfsae@ier.unam.mx, sjp@ier.unam.mx

1876-6102 © 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license

(http://creativecommons.org/licenses/by-nc-nd/3.0/).

Selection and/or peer-review under responsibility of ISES.

doi: 10.1016/j.egypro.2014.10.295

1. Introduction

Currently bioethanol is one of the most studied biofuel worldwide, because it can be a sustainable alternative for replacing fossil fuel [1]. In the case of Mexico, there has been boosting production in response to the shortage of fossil fuels nationally and internationally. Sugar cane has been one of the most used raw materials in the production of bioethanol. Brazil and USA are the world's largest bioethanol producers, using sugarcane and corn as the respective feedstocks. In the sugarcane industry, large amounts of lignocellulosic materials (sugarcane bagasse) are produced during sugar and ethanol production. Sugarcane bagasse is currently used as a fuel for supplying the energy required for the plant, while sugarcane trash, in earlier days was burnt to improve the cultivation, is today mostly left in the field for agricultural purposes [2]. However, there are various raw materials and wastes with a high content of fermentable sugars that can be evaluated for bioethanol production.

Mango (Mangifera indica L.) may be a case for this purpose because it is one of the most popular and abundant tropical fruits in Southeast Asia and is often in oversupply after each harvest [3]. This fruit is mainly grown in 85 countries. Asia and Eastern countries produce about 80 percent of total world production. There are a great number of varieties, which differ from each other with respect to crop, the color of the skin, pulp, the flavor and aroma of the fruit, among other features [4].

Mexico is the fifth producer of mango around the world. The main producers are India, China, Thailand, Pakistan and Mexico, followed by Indonesia. Together, these six nations generate three of every four tons of the fruit produced worldwide. The area of cultivation of mango in Mexico amounts to 186,505 hectors. Mexico has a production of 1.481 million tons according to the data reported by the SIAP in 2012 [5]. On the other hand, according to the latest report of SAGARPA, there is a history of losses amounting to 230 thousand tons per year. According to a report published by Reddy and Reddy in 2005, Mango contains a high concentration of sugar (16-18% w/v) and acids with organoleptic properties, and also contains antioxidants. Sucrose, glucose and fructose are the principal sugars in ripe mango, with small amounts of cellulose, hemicellulose and pectin [6].

2. Materials and methods

2.1. Raw material

The raw material (Mango Ataulfo (Mangifera indica L.)), which was employed for this work was dried with a solar dehydrator and milled. After the pretreatment, we conducted a thermal hydrolysis process (THP) at conditions of 130 °C and 15 psi for 20 min. After the pretreatment, it was centrifuged at 5000 rpm and 28 °C for 10 minutes (Centrifuge 5804R, 15 amp version) to clarify the substrate. The substrate was adjusted to a concentrations of reducing sugar of 100, 150 and 200 g/L, respectively according to the proposed experimental design.

2.2. Microorganism and inoculum preparation

The strain Saccharomyces cerevisiae Y2034 was provided by the ceparium of the Polytechnic University of Chiapas. Yeasts were maintained in sterile YPD solid culture media consisting of yeast extract, peptone, glucose and agar at concentrations of 10, 20, 20 and 18 g/L, respectively. They were stored at 4 °C. To prepare the inoculums of S. cerevisiae Y2034 a loop-full of cells were added to each 150 mL tube containing 100 mL sterile (121°, 20 min, 15 psi.) YPD medium liquid consisting of glucose, peptone and yeast extract at concentrations of 20, 20 and 10 g/L, respectively. The test tubes were incubated in a rotary shaker at 30 °C and 150 rpm for 24 h. The preparation protocol was in accordance with the literature [7] [8].

2.3 Fermentation

At the end of incubation, the contents of these tubes were used for fermentation. Fermentations were also carried out in 150 mL Erlenmeyer flasks with 100 mL medium, for 24 h. The agitation was fixed at 150 rpm (Temperature controlled shaker, Lusmistell models iro 70), at a pH of 4.5 and at 30 °C. The flasks were inoculated with 1x106 CFU/mL of S. cerevisiae Y2034. An Erlenmeyer flask containing hydrolysate with the addition of 5 g/L yeast extract, 5 g/L peptone, 5 g/L KH2PO4, 0.2 g/L (NH4)2SO4 and 0.4 g/L MgSO4.7H2O was used. All experiments were carried out in triplicate. Samples were taken at 0 h, 6 h, 12 h, 18 h and 24 h to analyze consumption of sugar and growth of yeast [7] [9].

2.4 Experimental design

The experimental strategy for the alcohol fermentation of the mango was carried out using the software, design-expert 8.0.7.1 (version 8.0.3, stat-ease, inc., minneapolis, USA). It is based on the methodology of response surfaces (RSM) based on the central composite design (CCD) 22 factorial.

2.5. Analytical methods and calculations

The total soluble solids (°Brix) and pH were measured at the indicated time points by using a pocket digital refractometer (SPER SCIENTIFIC, MOD. 300053) and a pH meter (OAKTON), respectively [10]. Appropriate dilutions from the growing culture suspensions were made. The cellular viability was determined by the Methyl Blue staining technique of direct counting using the neubauer camera [11]. The sugar concentration was estimated by the DNS technique or 3,5 Dinitrosalirilic acid method [12]. Each sample was analyzed in triplicate.

3. Results and discussion

3.1. Experimental strategy of alcohol fermentation

For mango fermentations the concentration of reducing sugar and yeast concentration were taken as input variables. Therefore, based on the proposed design we obtained the behavior of sugar consumption and cell density as shown in table 1. One can see that the treatments with 150 g/L initial reducing sugar using the pulp and peel show higher cell growth and sugar was reduced to 89 percent.

Table 1. Experimental design for the alcohol fermentation of mango.

Input Variables Output Variables

Sugar Sugar

concentration Cell Concentration (UFC/mL) consumption

(g/L) (g/L)

Initial Initial A B A B

1 100 1.00E+06 3.00E+07 5.00E+07 32.99 15.33

2 100 1.00E+06 3.50E+07 5.00E+07 32.1 14.4

3 100 1.00E+06 3.50E+07 6.50E+07 33.8 15.2

4 150 1.00E+06 8.70E+07 2.50E+08 47.11 17.94

5 150 1.00E+06 7.50E+07 2.55E+08 46.8 17.5

6 150 1.00E+06 9.50E+07 2.60E+08 47.33 16. 70

7 200 1.00E+06 1.00E+08 8.00E+07 80.1 47.25

8 200 1.00E+06 9.00E+07 9.00E+07 80.1 46.5

9 200 1.00E+06 1.05E+08 9.50E+07 81.01 46.85

A = pulp B = pulp + peel

3.2. Fermentations with mango pulp

In the process of alcohol fermentation, the kinetic data were obtained for the sugar and yeast. The behavior for each treatment is shown in Figure 1. These fermentations were carried out only with mango pulp. The results of these treatments showed that higher cell densities are given with 200 g/L of initial sugar, however reducing sugar in the sample concentration is not recommended for alcohol fermentation of mango pulp at high concentrations, given the fact the sugar is not completely metabolized and therefore there is a loss of 40 percent of the reducing sugar.

Fig. 1. Kinetic behavior of yeast and reducing sugar during alcohol fermentation with initial concentrations of 200 (♦), 150 (*) and

100 (•), g/L respectively of mango pulp.

Figure 2 shows the behavior of total soluble solids (SST), temperature and pH. It is noted that for the first parameter, decreasing ° Brix are higher than 50 percent of initial values. However, as demonstrated in figure 1 treatment with 200 g/L of initial sugar had the highest cell density. But, the best treatment is 150 g/L, because the sugar is reduced up to 70 percent and the cell density is very close to the higher density treatment. The temperature was stable at 30 ° C, as the pH is maintained in the range reported for the optimal development of this yeast (4.5-5).

0 * U LP H

Fig. 2. Behavior of the temperature (0), pH (□) and the SST with initial concentrations of 13.7 (A), 17 (o) and 22.3 (*),°Brix

respectively using mango pulp.

3.3. Fermentations with pulp and mango peel

During the development we proposed different experimental treatments, first with the sugar obtained directly from mango pulp. Later, treatments have been proposed using the full mango and using cellulosic waste as shown in Table 1. These fermentations were performed with pretreatments for obtaining most amount of reducing sugar. Figure 3 shows the results obtained from fermentation of the complete mango with different initial sugar. In this graph, it can be seen that the best treatment is the initial concentration of 150 g/L, because it is possible to obtain the highest number of cells and increased metabolization of sugar very close to 90 percent.

'ItanOnj

Fig. 3. Kinetic behavior of yeast and reducing sugar during alcohol fermentation with initial concentrations of 200 (♦), 150 (*) and

100 (•), g/L respectively using mango pulp and peel.

In these treatments the behavior of total soluble solids (° Brix), temperature and pH can be seen in figure 4, where it is displayed the treatments with 200 and 100 g/L initial sugar respectively. It is seen that there is a decrease of more than 50 percent of °Brix compared to the initial values. However, as demonstrated in figure 3, treatment with cell density was increased to 150 g/L of initial sugar and hence is the best treatment. In this treatment the sugar was reduced to around 90 percent. At the same time, the temperature was stable at 30 °C and the pH was maintained in the range reported for the optimal development of this yeast (4.5-5).

'Inno i.hrO

Fig. 4. Behavior of temperature (0), pH (□) and the SST with initial concentrations of 13.7 (A), 17 (o) and 22.3 (*), °Brix

respectively using mango pulp and peel.

4. Conclusion

Based on the results obtained in this study, the best concentration of initial sugar for fermentation of mango is 150 g/L. Under these conditions the cell number and sugar consumption were better than the other experimental treatments. The pulp, peel and seed of the mango provide fermentable sugars for the production of bioethanol. We established an appropriate methodology for alcohol fermentation of agricultural waste from mango for the evaluation of the production of bioethanol. The observed changes in the kinetics of the yeast are related to the composition of the medium, since the temperature and pH are

stable.

Acknowledgements

The authors thank the technical help received from M.C. Jose Campos in spectrophotometry analysis, Dr. Patricia Altuzar in FTIR measurement and M.C. Gildardo Casarubias in the technical help in general.

References

[1] Farrell, A.E., Plevin, R.J., Turner, B.T., Jones, A.D., O'Hare, M., Kammen, D.M.. Ethanol can contribute to energy and environmental goals. Science 2006; 311: 506-508.

[2] Alonso Pippo, W., Luengo, C.A., Alonsoamador Morales Alberteris, L., Garzone, P., Cornacchia, G., 2011. Energy recovery from sugarcane-trash in the light of 2nd generation biofuels. Part 1: Current situation and environmental aspects. Waste Biomass Valor 2, 1-16.

[3] Pino, J.A., Queris, O. Analysis of volatile compounds ofmango wine. Food Chemistry 2011; 125, 1141-1146.

[4] L.V.A. Reddya, O.V.S. Reddy. Effect of fermentation conditions on yeast growth and volatile composition of wine produced from mango (Mangifera indica L.) fruit juice. Food and bioproducts processing. 2011. 89: 487-491.

[5] SIAP. Servicio de Información Agroalimentaria y Pesquera 2012. [On line], http://www.siap.gob.mx. Agosto 2013.

[6] Reddy, L.V.A., Reddy, O.V.S.. Production and characterization of wine from mango fruits (Mangifera indica L.). World J. Microbiol. Biotechnol 2005a; 21, 1345-1350.

[7] Wen Wang, Xinshu Zhuang, Zhenhong Yuan, Qiang Yu, Wei Qi, Qiong Wang, Xuesong Tan. High consistency enzymatic saccharification of sweet sorghum bagasse pretreated with liquid hot water. Bioresource Technology 2012; 108: 252-257.

[8] Shen F, Kumar L, Hu J, Saddler JN. Evaluation of hemicellulose removal by xylanase and delignification on SHF and SSF for bioethanol production with steampretreated substrates. Bioresour Technol 2011; 102 (19): 8945-51.

[9] Gaber Z. Breisha. Production of 16% etanol from 35% sucrose. Biomass and bioenergy 2010; 34: 1243-1249.

[10]Xiao Li, Li Jie Chan, Bin Yu, Philip Curran, Shao-Quan Liu. Fermentation of three varieties of mango juices with a mixture of Saccharomyces cerevisiae and Williopsis saturnus var. mrakii. International Journal of Food Microbiology 2012; 158: 28-35.

[11] J.R. Postgate. Viable counts and viability. In Methods in Microbiology, 1967, Vol. 1, ed. Norris, J.R. and Ribbons, D.W. pp. 611- 628. New York: Academic Press.

[12] Miller, G.L. Use of dinitrosalicylic acid reagent for determination of reducing sugar. Anal. Chem 1959; 31: 426-428.