Production of bioethanol through enzymatic hydrolysis of potato

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1 Africn Journl of Biotechnology Vol. (), pp. 9-, Mrch, Aville online t DOI:.89/AJB.9 ISSN 8 Acdemic Journls Full Length Reserch Pper Production of ioethnol through enzymtic hydrolysis of potto Rhmt Ali Khn *, Allh Nwz, Mustq Ahmed, Muhmmd Rshid Khn, Fzl DinNsir Azm, Smi Ullh nd Frheen Sdullh, Akhlq Ahmd, Mir Sdiq Shh nd Nisr Khn Deprtment of Biotechnology, Fculty of Biologicl Sciences, University of Science nd Technology Bnnu, Khyer Pkhtunkhw, Pkistn. Deprtment of Biochemistry, Fculty of Biologicl Sciences, Quid-i-Azm University Islmd, Pkistn. Accepted Novemer, Due to grdul decrese in petroleum resources nd impcts of these wstes on the environment, there is need to utilize the wstes of pottoes to get welth out of wstes nd clen the environment. In this study, potto wstes were investigted s source of ioethnol. g potto powder ws mixed with L distilled wter in two seprte ekers to form potto slurry. Bioethnol production ws investigted using effect of ph, temperture nd mixture of digesting enzymes fter scrifiction nd fermenttion. The results show tht significnt (p<.) ioethnol ws produced t C nd t ph.. This investigtion lso revels tht mixture of enzymes significntly enhnced (p<.) ioethnol production compred to non treted mixture. Mximum ioethnol productions were due to the presence of sugr in pottoes. Key words: Bioethnol, potto, ph, temperture, liquefction. INTRODUCTION Due to grdul decrese of fossil fuels, ioethnol hs got the ttention of mny reserchers to use it s lterntive source of energy cross the world. Bioethnol is produced from the fermenttion of renewle resources for fuel or fuel dditives. Additionlly, ioethnol is considered to e produced from iomsssed mterils (Grssi et l., 999), insted of toxic methyl tert-utyl ether (MTBE) nd tert-myl methyl ether (TAMES). Bioethnol is lredy utilized s dditive of gsoline in mny prts of the world. Production of ioethnol s iofuel is the need of recent time, ecuse in mny countries of the world like the United Sttes nd Brzil tremendous reserch re going on this project. The world production of ioethnol hs reched up to million with United Sttes nd Brzil getting top position nd Indi on the fourth position. Bioethnol is produced from vrious griculture wstes *Corresponding uthor. E-mil: Rhmtgul_8@yhoo.com. Tel: nd sugr contining crops, vegetles nd fruits like sugr cne (Brzil), corn grin (United Sttes) nd strchy griculture wstes (Indi). According to the United Sttes Deprtment of energy for every unit of energy consumed for ioethnol production,. units of energy re returned (Hill et l., ). Sugry sustrtes nd cellulosic mterils re either expensive or involves mny steps for ioethnol production. Therefore crops which contined greter mount of strch re usully utilized for the ioethnol production such s crops like corn, rley, whet, rice, tuer crops, potto nd sweet potto. Production of ioethnol lso depends upon strins of yest such s Scchromyces cerevisie, suitle sustrte nd the methods employed for ioethnol production, gretly increse the efficiency of ioethnol production (Szmeln et l., ; Shigechi et l., ). For ethnol production, pottoes re chep sustrte ecuse it is rich in strch nd require less processing thn other grins. After suitle processing, good qulity of ethnol cn e produced from pottoes which cn e used for oth fuel s well s potle purpose. Rotten pottoes re used for the

2 Afr. J. Biotechnol. Figure. Flow sheet of ioethnol production from wste pottoes. production of ioethnol. As y products, rotten pottoes re otined from to % of the crops in potto cultivtion (Kimmo nd Liis 999). In Pkistn, there re millions of potto wstes nd rotten pottoes re produced per yer. This requires specil considertion to utilize these wste pottoes for ioethnol production. In this study, we utilized potto wstes nd rotten pottoes otined from domestic dumping sides nd locl vegetles mrket for ioethnol production using different ph, temperture nd mixture of enzymes for strch hydrolysis. ws dded to one of the potto solution nd the other contined only potto slurry. Both solutions were heted t 9 to C for to min in utoclve to liquefy the strch nd the ph ws djusted to.8. Scchrifiction After cooling, the slurries were mixed with µl of glucomylse enzyme to convert the strch into the fermentle sugr nd lso commercil yest (S. cerevisie) ws dded to oth solutions s descried y Oghgren et l. (). MATERIALS AND METHODS Smple collection nd tretment Potto wstes nd rotten pottoes were collected from the vegetle mrket of District Bnnu nd from the domestic dumping sides. These wste mterils were cut into pieces, wshed, dried nd ground mechniclly (Figure ). Formtion of slurries nd liquefction seprte ekers to form potto slurry. µl of mylse enzymes Fermenttion nd distilltion g potto powder ws mixed with L distilled wter in two After proper mixing, oth solutions were seled tightly (neroic fermenttion) s shown in Figure nd incuted t C, nd 8 to C to estimte the effect of temperture on ioethnol production. During this period, sugr units were fermented to ioethnol y the yest nd mixture of enzymes. After fermenttion, unfermented residues were filtered while filtrte (ioethnol) ws distilled with rotry evportor t 8. C. The ioethnol otined ws used s iofuel fter the ddition of to % of gsoline to get nhydrous ioethnol (Kroumov et l., ) while the unfermented solid residues (stillge) ws used s vlule niml feed stocks

3 Khn et l. 9 8 Ethnol production (%) c Different temperture ( C) Figure. Percentge of ethnol production., C; nd, C; different letter shows significnce t p<.. Sttisticl nlysis The tulted dt of vrious tretments were expressed s the men ± SE for the three replictes in ech group. Computer softwre SPSS ws used to determine the differences etween groups using one-wy nlysis of vrince (ANOVA). Lest significnt difference (LSD) ws determined using inter group comprisons t proility level of.%. RESULTS Temperture effects the production of ioethnol. Dt of our this study express tht significntly (p<.) mximum ioethnol ws produced t C, s compred to ioethnol produced t C nd 8 C respectively s shown in Figure. ph of the medi lso effect ioethnol production. Dt of our study express tht considerle (p<.) ioethnol ws produced t ph., s compred to ioethnol produced t ph nd (Figure ). The ioethnol production lso depends on process. Dt of the study show tht mximum ioethnol ws recovered fter tretment with oth enzymes nd yest s compred to conventionl method proceed with yest only (Figure ). Vrious tretments of ioethnol production lso ffect the stillge of the remining process. Figure revels tht considerle (p<.) mount of stillge were produced with pottoes treted with mixture of enzymes s compred to residue otined from non treted enzymtic pottoes in this process. DISCUSSION Recently, due to shortge in nturl resources of petrochemicl nd nturl gs, reserchers hve focused to produce new renewle energy resources. To chieve this gol, scientists tke interest on the production of ioethnol using iomss nd griculture wstes. Potto possesses gret mount of strch tht cn e redily hydrolysed into sugrs tht could e esily fermented to produce ioethnol nd found suitle to e used s lterntive energy source (Chndel et l., ). Temperture effects the production of ioethnol. Three different tempertures;, 8 nd C were used in this study to find the effect of temperture on ioethnol production through fermenttion. Dt of this study reveled tht significnt (p<.) % ioethnol were produced t high temperture s shown in Figure. This might e due to the inpproprite temperture condition contriuting to the lck of metolic ctivity which consequently gve n effect on the diffusion of sustrte nd product (Alin et l., 98). Growth of microes requires optimum ph nd production of ioethnol is effected with different ph vlues. ph vlues of ioethnol exhiited significnt difference sed on ANOVA method t p<.. The production of ioethnol ws mximum t ph. compred to ph nd. Process of fermenttion lso effects ioethnol production from pottoes. Yest is necessry for fermenttions while ddition of enzyme increses process of ioethnol production nd enhnces conversion of strch into sugr. In this study, two sets were used to produce ioethnol from pottoes.

4 Afr. J. Biotechnol. Bioethnol production (%) c Tretment groups t different ph Figure. Percentge of ethnol production t different ph.,.;, ;,. Different letter shows significnce t p<.. 9 Bioethnol production (%) 8 Tretment group Figure. Percentge of ethnol production t different tretment., Treted with mixture of enzymes;, treted with conventionl method. Different letter shows significnce t p<.. In one set, we used mixture of enzymes while the other ws treted with yest lone. Dt revel tht mximum production of ioethnol ws chieved from enzymtic hydrolysis compred to yest treted sets. Similr results were documented y other study during ioethnol production from strchy nd sugr contining sources (Hossin et l., ). Conclusions Energy crisis forces reserchers to find new nd low cost sources for ethnol production. In this study, pottoes were used for ethnol production. Experimentl results show tht pottoes possesses high mount of reducing sugrs. In Pkistn, it is our first ttempt to produce

5 Khn et l. Stillge production (%) Tretment group Figure. Percentge of stillge production t different tretments.,treted with mixture of enzymes;, treted with conventionl method. Different letter shows significnce t p<.. ioethnol from strchy griculture wstes which on one side provides ioethnol for iofuel while on the other hnd reduce environmentl pollution. A comprtive study on ioethnol production from the wstes of potto ws crried out. It is concluded tht potto wstes hve greter mount of strch, nd produced high ioethnol through enzymtic hydrolysis. ACKNOWLEDGEMENTS We re thnkful to the Directorte of Science nd Technology (DOST) Khyer Puktun Khw (KPK), Pkistn for the provision of finncil ssistnce under the project title Bioethnol production from strchy griculture wstes through enzymtic hydrolysis. All the uthors re lso thnkful to Prof. Dr. Asmt Ullh Khn, nd the Vice Chncellor of the University of Science nd Technology for their support throughout the project. REFERENCES iodiesel nd ethnol iofuels. Proc. Of the Nt. Acd. Sci. USA, : -. Hossin ABMS, Ahmed SA, Ahmed M, Fris M A, Annur MSM, Hdeel M, Hmmd N (). Bioethnol fuel production from rotten nn s n environmentl wste mngement nd sustinle energy. Afric. J. Biotech. : Kimmo V, Liis M (999). Bioetnolin vlmistus jäteperunst Esiselvitys teknisestä toteutuksest j tloudellinen rviointi, Report 9, Oulun yliopisto, Prosessitekniikn ossto. Kroumov AD, Modenes AN, De Arujo MC (). Development of new unstructured model for simultneous scchrifiction nd fermenttion of strch to ethnol y recominnt strin. J. Biochem. Eng. 8: -. Oghgren KH, Hhn B, Zcchi G (). Simultneous scchrifiction nd co fermenttion of glucose nd xylose in stem pretreted corn stover t high fier content with S.cerevisie. J. Biotechnol. : Shigechi H, Koh J, Fujit Y, Mtsumoto T, Bito Y, Ued M, Stoh E nd Kondo A () Direct production of ethnol from rw corn strch vi fermenttion y use of novel surfce- engineered yest strin codisplying glucomylse nd lphmylse. Appl. Environ. Microiol. : -. Szmeln K, Nowk J, Czrnecki Z () Use of Zymomons moilis nd Scchromyces cerevisie mixed with Kluyveromyces frgilis for improved ethnol production from Jeruslem rtichoke tuers. Biotechnol. Lett. : Alin K, Georges AN, Ak Y (98). Ethnol production form pinepple juice in Côte d Ivoire with preselected yest strins. J. Ferment. Technol. (): -8. Chndel AK, Rudrvrm R, Nrsu ML, Ro V, Rvindr P (). Economics nd environmentl impcts of ioethnol production technologies: n pprisl. Biotechnol. Mol. Biol. Rev. (): -. Grssi G (999). Modern ioenergy in the Europen Union renewle energy, : Hill J, Nelson E, Tilmn D, Polsky S nd Tiffncy D () Environmentl, economic nd energetic costs nd enefits of