Sains Malaysiana 50(2)(2021): 409-418

http://dx.doi.org/10.17576/jsm-2021-5002-12

Penghasilan Asid Laktik D daripada Hidrolisat Sabut Kelapa Tua dan Muda

(Production of D Lactic Acid from Hydrolysate Brown and Green Coconut Husk)

NUR NADHIRAH MUHAMAD NOR, TEO PUI LENG, NUR AKMAL SOLEHAH DIN & NURUL AQILAH MOHD ZAINI*

Jabatan Sains Makanan, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 46300 UKM Bangi, Selangor Darul Ehsan, Malaysia

Received: 4 March 2020/Accepted: 18 August 2020

ABSTRAK

Penghasilan asid laktik D semakin mendapat perhatian kerana sifat polimernya, poli asid laktik D, yang termostabil. Kajian ini dijalankan untuk menghasilkan asid laktik D daripada sisa pertanian yang tidak bernilai tinggi seperti sabut kelapa tua (SKT) dan sabut kelapa muda (SKM) melalui teknologi fermentasi. Peringkat pertama kajian, SKT dan SKM dikenakan pra-rawatan beralkali menggunakan 5% larutan natrium hidroksida pada suhu 121 °C selama 15 minit untuk menyingkirkan komponen lignin dan hemiselulosa. Kemudian, dua kaedah hidrolisis dikaji, iaitu hidrolisis berenzim dengan menggunakan enzim Acellerase 1500 (1, 5 dan 10%, i/i) dan hidrolisis berasid dengan menggunakan asid sulfurik (1, 3 dan 5%, i/i). Keputusan menunjukkan hidrolisis berenzim dengan kepekatan 10% enzim Accellerase 1500 (11.09 mg/mL) lebih cekap menukarkan selulosa kepada gula penurun berbanding hidrolisis berasid (0.87 mg/mL) dalam hidrolisat SKT. Manakala, bagi hidrolisat SKM, 5% enzim Accellerase menghasilkan kepekatan gula penurun yang lebih tinggi berbanding hidrolisis berasid dengan 15.00 dan 1.02 mg/mL. Kadar penukaran gula penurun yang maksimum didapati daripada hidrolisis berenzim SKT dan SKM dengan 55% dan 60%. Pada peringkat kedua, hidrolisat yang mengandungi gula penurun yang tinggi digunakan sebagai sumber karbon untuk penghasilan asid laktik D oleh Lactobacillus coryniformis subsp. torquen melalui proses fermentasi (48 jam, 37 ºC, 150 rpm). Pada akhir proses fermentasi, sebanyak 4.93 g/L penghasilan asid laktik D direkodkan dalam kaldu hidrolisat SKT dan 3.98 g/L asid laktik D terhasil dalam kaldu hidrolisat SKM dengan pH kaldu fermentasi tidak dikawal. Kesimpulannya, selulosa dalam kedua-dua sampel SKT dan SKM boleh diuraikan kepada gula penurun melalui hidrolisis berenzim dan seterusnya berpotensi untuk digunakan sebagai substrat bagi menghasilkan asid laktik D melalui proses fermentasi.

Kata kunci: Asid laktik D; biojisim sabut kelapa; hidrolisis berenzim; hidrolisis berasid; proses fermentasi

ABSTRACT

Production of D lactic acid is gaining attention due to thermostable properties of its polymer, Poly-D-lactic acid. This study was conducted to produce D lactic acid from low-value agricultural waste such as brown coconut husk (SKT) and green coconut husk (SKM) through fermentation technology. In the first phase of the study, SKT and SKM were pre-treated with alkaline solution using 5% sodium hydroxide solution at 121 ° C for 15 min to remove lignin and hemicellulose components. Then, two hydrolysis methods were studied, namely enzymatic hydrolysis using Acellerase 1500 (1, 5 and 10%, v/v) and acidic hydrolysis using sulfuric acid (1, 3 and 5%, v/v). The results showed that 10% Accellerase 1500 (11.09 mg/mL) was more efficient in converting cellulose to reduced sugar than acidic hydrolysis (0.87 mg/mL) in SKT hydrolysis. Meanwhile, for SKM hydrolysis, 5% Accellerase enzyme yielded a higher sugar concentration than acidic hydrolysis with 15.00 and 1.02 mg/mL, respectively. The highest conversion rates of sugar were obtained from the hydrolysis of SKT and SKM by 55% and 60%, respectively. In the second stage of this research, hydrolysate of high reducing sugars was used as a carbon source for the production of D lactic acid by Lactobacillus coryniformis subsp. torquen through the fermentation (48 h, 37 ºC, 150 rpm). At the end of the fermentation process, 4.93 g/L of lactic acid production was recorded in SKT hydrolysate and 3.98 g/L lactic acid was produced in SKM hydrolysate, where the pH of the fermentation broth was not controlled. In conclusion, cellulose in both SKT and SKM samples can be hydrolysed into reducing sugars through enzymatic hydrolysis and subsequently shows potential to be used as a substrate for D lactic acid production through fermentation.

Keywords: Acidic hydrolysis; coconut husk biomass; D lactic acid; enzymatic hydrolysis; fermentation

REFERENCES

Abdel-Rahman, M.A., Tashiro, Y. & Sonomoto, K. 2010. Lactic acid production from lignocellulose-derived sugars using lactic acid bacteria: Overview and limits. Journal of Biotechnology 156(4): 286-301.

Aryani, E., Kusumo, E. & Supartono. 2013. Produksi bioetanol dari jerami padi (Oryza sativa L). Jurnal Institut Teknologi Nasional 2(2): 168-172.

Bensah, E.C. & Mensah, M. 2013. Chemical pretreatment methods for the production of cellulosic ethanol: Technologies and innovations. International Journal of Chemical Engineering 2013: Article ID. 719607.

Borshchevskaya, L.N., Gordeeva, T.L., Kalinina, A.N. & Sineokii, S.P. 2016. Spectrophotometric determination of lactic acid. Journal of Analytical Chemistry 71(8): 755-758.

Bukhari, N.A., Loh, S.K., Bakar, N.A. & Ismail, M. 2017. Hydrolysis of residual starch from sago pith residue and its fermentation to bioethanol. Sains Malaysiana 46(8): 1269-1278.

Chen, H., Zhao, X. & Liu, D. 2016. Relative significance of the negative impacts of hemicelluloses on enzymatic cellulose hydrolysis is dependent on lignin content: Evidence from substrate structural features and protein adsorption. ACS Sustainable Chemistry & Engineering 4(12): 6668-6679.

Ciftci, D. & Saldana, M.D.A. 2015. Hydrolysis of sweet blue lupin hull using subcritical water technology. Bioresource Technology 194: 75-82.

Dumbrepatil, A., Adsul, M., Chaudhari, S., Khire, J. & Gokhale, D. 2008. Utilization of molasses sugar for lactic acid production by Lactobacillus delbrueckii subsp. delbrueckii mutant Uc-3 in batch fermentation. Appl. Environ. Microbiol. 74: 333-335.

Garrett, B.G., Srinivas, K. & Ahring, B.K. 2015. Performance and stability of Amberlite™ IRA-67 ion exchange resin for product extraction and pH control during homolactic fermentation of corn stover sugars. Biochemical Engineering Journal 94: 1-8.

Garriga, M., Almaraz, M. & Marchiaro, A. 2017. Determination of reducing sugars in extracts of Undaria pinnatifida (harvey) algae by UV-visible spectrophotometry (DNS method). Desarrollo E Innovación En Ingeniería2007: 173-179.

Han, L., Feng, J., Zhang, S., Ma, Z., Wang, Y. & Zhang, X.  2012. Alkali pretreated of wheat straw and its enzymatic hydrolysis. Brazilian Journal of Microbiology 43(1): 53-61.

Hu, F. & Ragauskas, A. 2012. Pretreatment and lignocellulosic chemistry. Bioenergy Research 5(4): 1043-1066.

Jones, P.O. & Vasudevan, P.T. 2010. Cellulose hydrolysis by immobilized Trichoderma reesei cellulase. Biotechnology Letters 32(1): 103-106.

Jungnikl, K., Paris, O., Fratzl, P. & Burgert, I. 2008. The implication of chemical extraction treatments on the cell wall nanostructure of softwood. Cellulose 15(3): 407-418.

Kim, I. & Han, J.I.  2012. Optimization of alkaline pretreatment conditions for enhancing glucose yield of rice straw by response surface methodology. Biomass and Bioenergy 46: 210-217.

Kucharska, K., Rybarczyk, P., Hołowacz, I., Łukajtis, R., Glinka, M. & Kamiński, M. 2018. Pretreatment of lignocellulosic materials as substrates for fermentation processes. Molecules 23(11): 2937.

Lin, Y. & Tanaka, S. 2006. Ethanol fermentation from biomass resources: Current state and prospects. Applied Microbiology and Biotechnology 69(6): 627-642.

Lomelí-Ramírez, M.G., Anda, R.R., Satyanarayana, K.G., de Muniz, G.I.B. & Iwakiri, S. 2018. Comparative study of the characteristics of green and brown coconut fibers for the development of green composites. BioResources 13(1): 1637-1660.

Mansuit, H., Samsuri, M.D.C., Sipaut, C.S., Yee, C.F., Yasir, S.M. & Mansa, R. 2015. Effect of varying acid hydrolysis condition in Gracilaria sp. fermentation using sasad. In IOP Conference Series: Materials Science and Engineering 78(1): 012004.

Mohamed, R., Lim, M.T. & Halis, R. 2013. Biodegrading ability and enzymatic activities of some white rot fungi on kenaf (Hibiscus cannabinus). Sains Malaysiana 42(10): 1365-1370.

Mohd Zaini, N.A., Chatzifragkou, A. & Charalampopoulos, D. 2019. Microbial production of d-lactic acid from dried distiller’s grains with solubles. Engineering in Life Sciences 19(1): 21-30.

Ringkas, G. 2016. The effect of various pretreatment methods on empty fruit bunch for glucose production. Malaysian Journal of Analytical Sciences 20(6): 1474-1480.

Robinson, P.K. 2015. Enzymes: Principles and biotechnological applications. Essays in Biochemistry 59: 1-41.

Sommer, S.G., Hamelin, L., Olesen, J.E., Montes, F., Jia, W., Chen, Q. & Triolo, J.M. 2016. Agricultural waste biomass. In Supply Chain Management for Sustainable Food Networks, edited by Iakovou, E., Bochtis, D., Vlachos, D. & Aidonis, D. New York: John Wiley & Sons, Ltd. pp. 67-106.

Soontornchaiboon Waesarat, Kim, S.M. & Pawongrat, R. 2016. Effects of alkaline combined with ultrasonic pretreatment and enzymatic hydrolysis of agricultural wastes for high reducing sugar production. Sains Malaysiana 45(6): 955-962.

Yang, X. 2006. Running LEO 1450VP SEM. Saint Mary's University.

Yew, B.S., Muhamad, M.A. & Moha, S.B. 2019. Effect of alkaline treatment on structural characterisation, thermal degradation and water absorption ability of coir fibre polymer composites. Sains Malaysiana 48(3): 653-659.

Ysuhaimi. 2018. Kelapa: Analisis Industri. http://myagri.com.my/2018/03/analisa-industri-kelapa/. Diakses pada 18 Mac 2019.

Zaini, N.A.B.M., Chatzifragkou, A. & Charalampopoulos, D. 2019. Alkaline fractionation and enzymatic saccharification of wheat dried distillers grains with solubles (DDGS). Food and Bioproducts Processing 118: 103-113.

*Corresponding author; email: nurulaqilah@ukm.edu.my