Khatun Most Sheauly, Hassanpour Morteza, Mussatto Solange I, Harrison Mark D, Speight Robert E, O'Hara Ian M, Zhang Zhanying
Centre for Agriculture and the Bioeconomy, Faculty of Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia.
School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia.
Bioresour Bioprocess. 2021 Sep 3;8(1):85. doi: 10.1186/s40643-021-00438-7.
Fructooligosaccharides (FOS) can be used as feed prebiotics, but are limited by high production costs. In this study, low-cost sugarcane molasses was used to produce whole-cell biocatalysts containing transfructosylating enzymes by Aureobasidium pullulans FRR 5284, followed by FOS production from molasses using the whole-cells of A. pullulans. A. pullulans in molasses-based medium produced cells and broth with a total transfructosylating activity of 123.6 U/mL compared to 61.0 and 85.8 U/mL in synthetic molasses-based and sucrose-based media, respectively. It was found that inclusion of glucose in sucrose medium reduced both transfructosylating and hydrolytic activities of the produced cells and broth. With the use of pure glucose medium, cells and broth had very low levels of transfructosylating activities and hydrolytic activities were not detected. These results indicated that A. pullulans FRR 5284 produced both constitutive and inducible enzymes in sucrose-rich media, such as molasses while it only produced constitutive enzymes in the glucose media. Furthermore, treatment of FOS solutions generated from sucrose-rich solutions using an invertase-deficient Saccharomyces yeast converted glucose to ethanol and acetic acid and improved FOS content in total sugars by 20-30%. Treated FOS derived from molasses improved the in vitro growth of nine probiotic strains by 9-63% compared to a commercial FOS in 12 h incubation. This study demonstrated the potential of using molasses to produce FOS for feed application.
低聚果糖（FOS）可用作饲料益生元，但受高生产成本限制。本研究中，利用低成本的甘蔗废蜜，通过出芽短梗霉FRR 5284生产含转果糖基酶的全细胞生物催化剂，随后使用出芽短梗霉的全细胞从废蜜中生产低聚果糖。在基于废蜜的培养基中，出芽短梗霉产生的细胞和发酵液的总转果糖基活性为123.6 U/mL，而在基于合成废蜜和蔗糖的培养基中分别为61.0 U/mL和85.8 U/mL。研究发现，在蔗糖培养基中添加葡萄糖会降低所产生细胞和发酵液的转果糖基活性和水解活性。使用纯葡萄糖培养基时，细胞和发酵液的转果糖基活性水平很低，且未检测到水解活性。这些结果表明，出芽短梗霉FRR 5284在富含蔗糖的培养基（如废蜜）中产生组成型酶和诱导型酶，而在葡萄糖培养基中仅产生组成型酶。此外，使用缺乏转化酶的酿酒酵母处理富含蔗糖溶液产生的低聚果糖溶液，可将葡萄糖转化为乙醇和乙酸，并使总糖中的低聚果糖含量提高20 - 30%。与市售低聚果糖相比，经处理的源自废蜜的低聚果糖在12小时培养中使9种益生菌菌株的体外生长提高了9 - 63%。本研究证明了利用废蜜生产用于饲料应用的低聚果糖的潜力。
