Formation and degradation of individual GOS formed by <i>B. breve</i> β-gal I (A) and β-gal II (B) during lactose conversion.

<p>Reaction conditions: initial lactose concentration of 200 g L<sup>−1</sup> in 50 mM sodium phosphate buffer (pH 6.5) with 1 mM Mg<sup>2+</sup> and 30°C and 1.0 U<sub>Lac</sub> mL<sup>−1</sup> β-gal I or 2.5 U<sub>Lac</sub> mL<sup>−1</sup> β-gal II. Symbols: (•) D-Gal<i>p</i>-(1→6)-D-Glc; (▪) D-Gal<i>p</i>-(1→6)-D-Gal; (▴) Gal<i>p</i>-(1→3)-D-Gal; (Δ) D-Gal<i>p</i>-(1→3)-D-Glc; (□) D-Gal<i>p</i>-(1→3)-D-Lac; (○) D-Gal<i>p</i>-(1→4)-Lac, (+) D-Gal<i>p</i>-(1→6)-D-Lac.</p>