LACTOBACİLLUS SANFRANCİSCENSİS’İN GELİŞMESİNDE ETKİLİ BİYOPROSES PARAMETRELERİNİN BELİRLENMESİ VE OPTİMİZASYONU

Son yıllarda, eski bir ekmek üretim metodu olan ekşi hamur ekmeğine yönelik talep artmıştır. Lactobacillus sanfranciscensis, heterofermantatif laktik asit bakterisidir ve maltozu kullanarak yüksek miktarlarda laktik asit ve asetik asit üreterek hamurun ekşimesine sebep olmaktadır. Bu çalışmada, farklı parametrelerinin L. sanfranciscensis’in gelişmesi üzerine etkisi incelenmiştir. En uygun azot kaynağı olarak maya ekstraktı, en uygun karbon kaynağı ise, maltoz olarak belirlenmiştir. En yüksek optik yoğunluk değerine fermantasyonun 48. saatinde ulaşılmıştır. pH, maltoz, maya ekstraktı ve Tryptic Soy Broth konsantrasyonlarının bakteri gelişimine etkisi incelenmiş ve bu parametrelerin optimum değerleri sırasıyla pH 6.5, %2 (w/v), %1.7 (w/v), %0.6 (w/v) olarak belirlenmiştir. Belirlenen optimum koşullar altında maksimum optik yoğunluk değeri 1.120±0.007 (biyokütle konsantrasyonu: 1.818±0.002 g/L) olarak bulunmuştur.

Anahtar Kelimeler:

Lactobacillus sanfranciscensis, starter kültür, optimizasyon, optik yoğunluk, azot kaynağı

DETERMINATION AND OPTIMIZATION OF THE BIOPROCESS PARAMETERS EFFECTING GROWTH OF LACTOBACILLUS SANFRANCISCENSIS

In recent years, there is an increasing demand for sourdough bread, which is one of the oldest methods of bread production. Lactobacillus sanfranciscensis is a heterofermentative lactic acid bacteria which produce large amounts of lactic acid and acetic acid from maltose and thus it is responsible for souring activity in sourdough. In this study, the effect of different cultivation parameters on the growth of L. sanfranciscensis has been evaluated. Maximum optical density was obtained at the 48th hour of the fermentation. Yeast extract was determined as the most appropriate nitrogen source and maltose was determined as the most appropriate carbon source. The optimum levels of pH, maltose, yeast extract and Tryptic Soy Broth were found as pH 6.5, 2% (w/v), 1.7% (w/v), 0.6% (w/v), respectively. Under optimized conditions, the optical density of 1.120±0.007 was obtained which corresponds to a biomass dry weight of 1.818±0.002 g/L.

Keywords:

Lactobacillus sanfranciscensis, starter culture, optimization, optical density, nitrogen source,

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