Sains Malaysiana 39(6)(2010): 891–899

Optimisation of Ammonium Tartrate and Glucose Concentration for Gamma Linolenic Acid Production by Cunninghamella sp. 2A1.

(Pengoptimuman Kepekatan Ammonium Tartarat dan Glukosa Terhadap Penghasilan  Asid Gamma Linolenik oleh Cunninghamella sp. 2A1.)

Farhila Muhid, Abdul Jalil Abdul Kader, Wan Mohtar  Wan Yusoff,

Othman Omar & Aidil Abdul Hamid*

School of Biosciences and Biotechnology

Faculty of Science and Technology, Universiti Kebangsaan Malaysia,

43600 Bangi, Selangor, Malaysia.

Received: 21 October 2009 / Accepted: 11 February 2010

ABSTRACT

The effects of ammonium tartrate and glucose concentration on biomass, lipid and GLA accumulation in Cunninghamella sp. 2A1 were investigated using Response Surface Methodology (RSM). Cultivation was carried out in 250 mL shake flask containing 100 mL of nitrogen limiting medium (with various combinations of concentration of ammonium tartrate (1-3 g/L) and glucose (30-60 g/L) at 30°C and 250 rpm agitation for 120 h. The concentration of both compounds significantly affected the biomass, lipid and GLA yield (p<0.05), with the production of each of them being represented by quadratic models. Higher concentration of ammonium tartrate and glucose (2.99 and 59.33 g/L, respectively) was required for enhanced biomass production whereas low nitrogen content with excess glucose was otherwise favoured for lipid and GLA production. Ammonium tartrate and glucose concentration at 1 and 43 g/L, respectively were estimated by the model and proven to give the highest lipid production and GLA yield of 31.06 % (g/g biomass) and 4.15 ×10^-2 (g/g lipid less biomass), respectively.

Keywords: C/N ratio; Cunninghamella sp.; gamma linolenic acid; lipid; Response Surface Methodology (RSM)

ABSTRAK

Kesan kepekatan ammonium tartarat dan glukosa terhadap penghasilan biojisim, lipid dan GLA oleh Cunninghamella sp. 2A1 dikaji menggunakan Kaedah Gerak balas Permukaan (RSM). Pengkulturan dilakukan dalam kelalang goncangan 250 mL yang mengandungi 100 mL medium terhad nitrogen (dengan pelbagai kombinasi kepekatan ammonium tartarat (1-3 g/L) dan glukosa (30-60 g/L) pada 30°C dengan kadar goncangan 250 rpm selama 120 j. Kepekatan kedua-dua sebatian ini memberi kesan signifikan terhadap penghasilan biojisim, lipid dan GLA (p<0.05) yang masing-masing diwakili oleh model kuadratik. Kepekatan ammonium tartarat dan glukosa yang lebih tinggi iaitu masing-masing pada 2.99 dan 59.33 g/L, didapati perlu untuk merangsang penghasilan biojisim sedangkan kandungan ammonium tartarat yang rendah dengan kepekatan glukosa yang tinggi pula diperlukan untuk membantu meningkatkan penghasilan lipid dan GLA. Kepekatan ammonium tartarat dan glukosa masing-masing pada 1 dan 43 g/L telah dianggarkan oleh model tersebut dan terbukti memberikan penghasilan lipid dan GLA tertinggi iaitu masing-masing sebanyak 31.06 % (g/g biojisim) dan 4.15 × 10^-2 (g/g biojisim tanpa lipid).

Kata kunci: Nisbah C/N; asid gamma linolenik; Cunninghamella sp.; lipid; Kaedah Gerak Balas Permukaan (RSM)

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*Corresponding author; email: aidilah@ukm.my