Enhanced β-fructofuranosidase biosynthesis by Rhodotorula glutinis using Taguchi robust design method

Coproduction of inulinase and invertase by Galactomyces geotrichum in whey-based medium and evaluation of additional nutrients

The purpose of this research was to evaluate the suitability of whey as an effective medium for the coproduction of inulinase and invertase by an oleaginous yeast Galactomyces geotrichum and to investigate the effects of some additional carbon and nitrogen sources. The nutritional factors and composition of the medium have a great impact on the production pathways of microbial enzymes. To deepen the research, a Taguchi design was employed to quickly scan the best conditions. First, the cheese whey was partly deproteinized and investigated as the sole medium for the yeast. The next step was performed to study the effects of inulin, sucrose and lactose as carbon sources and ammonium sulfate, yeast extract and casein as nitrogen sources. All analyses (Taguchi and ANOVA) were performed using Minitab software. Whey-based medium without any additional carbon and nitrogen sources gave inulinase and invertase activities as 54.6 U/mL and 47.4 U/mL, respectively. Maximum inulinase activity was obtained as 77.9 U/mL using inulin as the carbon source without any nitrogen source. The highest I/S ratio was found as 2.08. On the other hand, the highest invertase activity was carried out as 50.85 U/mL in whey-based medium using lactose as carbon source without any additional nitrogen source. This is the first report about partly deproteinized whey-based medium utilization for simultaneous inulinase and invertase production by G. geotrichum TS-61. Moreover, the effects of carbon and nitrogen sources were investigated in detail.

Rhodotorula sp. as a cell factory for production of valuable biomolecules

Rhodotorula sp. are well-known for their ability to biosynthesize a diverse range of valuable biomolecules, including carotenoids, lipids, enzymes, and polysaccharides. Despite the high number of studies conducted using Rhodotorula sp. at the laboratory scale, most of these do not address all processual aspects necessary for scaling up these processes for industrial applications. This chapter explores the potential of Rhodotorula sp. as a cell factory for the production of distinct biomolecules, with a particular emphasis on exploring their use from a biorefinery perspective. Through in-depth discussions of the latest research and insights into non-conventional applications, we aim to provide a comprehensive understanding of Rhodotorula sp.'s ability to produce biofuels, bioplastics, pharmaceuticals, and other valuable biochemicals. This book chapter also examines the fundamentals and challenges associated with the optimizing upstream and downstream processing of Rhodotorula sp-based processes. We believe that through this chapter, readers with different levels of expertise will gain insights into strategies for enhancing the sustainability, efficiency, and effectiveness of producing biomolecules using Rhodotorula sp.

Biosynthesis of lactosucrose by a new source of β-fructofuranosidase from Bacillus methanolicus LB-1

Lactosucrose (LS) is a prebiotic trisaccharide enzymatically synthesized by transglycosylation from lactose and sucrose with beneficial health effect. The β-fructofuranosidase used for synthesis of LS was produced from Bacillus methanolicus LB-1, which was isolated from traditional rice wine. A maximal yield of 8.63 U/mL of the enzyme was obtained by fermentation with B. methanolicus LB-1 under the optimized conditions: 10 g/L of glucose, 5 g/L of yeast extract, initial medium pH at 7.0, 37 °C, 24 h. The enzyme was purified and identified by ammonium sulfate fractional precipitation, Sephadex G-75 gel filtration chromatography and LC-MS, and SDS-PAGE of the purified enzyme showed a major protein band at 45 kDa. Biosynthesis of LS was performed using the purified β-fructofuranosidase, and production of LS reached 110 g/L under the optimized reaction conditions: pH at 7.0, 37 °C, 6.0 U/g sucrose of enzyme, 15% of sucrose, 15% of lactose, 28 h. HPLC analysis of the reaction products showed a distinct peak for LS at about 30 min of elution, confirming that B. methanolicus LB-1 β-fructofuranosidase had effective transfructosylation activity. Therefore, this new microbial source of β-fructofuranosidase may be a candidate with potential application prospect in biosynthesis of prebiotic LS.

Optimization of inulinase production using Jerusalem artichoke (Helianthus tuberosus) as cheap substrate and comparison with pure chicory inulin

Jerusalem artichoke (JA) is a nutritional vegetable for human diet depending on its natural structure, especially high inulin content and it is the second inulin source for commercial production in the world, after chicory. It was aimed to investigate the inulinase production capability of Galactomyces geotrichum TS61 (GenBank accession: MN749818) using JA as an economical and effective substrate comparing with the pure chicory inulin and to optimize the fermentation using Taguchi design of experiment (DOE) in this study. Besides, the effects of sucrose on inulinase production either combined with JA or in its absence were also studied. Taguchi L16 orthogonal array was employed for optimization. Both of inulinase activities obtained from JA and pure inulin gave the maximum result at the 10th experimental run as 40.21 U/mL and 57.35 U/mL, respectively. The optimum levels were detected for each factor as, 30 g/L JA, 30 g/L sucrose, pH 5.5, and four days for time. The predicted value was found as 41.63 U/mL that was similar to the obtained result as 41.17 U/mL. Finally, inulinase activity was increased approximately 8-folds after optimization. The sucrose-free medium had similar effects with higher concentrations of JA at long incubation time. This is the first investigation about inulinase production by G. geotrichum.

The β-Fructofuranosidase from Rhodotorula dairenensis: Molecular Cloning, Heterologous Expression, and Evaluation of Its Transferase Activity

The β-fructofuranosidase from the yeast Rhodotorula dairenensis (RdINV) produces a mixture of potential prebiotic fructooligosaccharides (FOS) of the levan-, inulin- and neo-FOS series by transfructosylation of sucrose. In this work, the gene responsible for this activity was characterized and its functionality proved in Pichia pastoris. The amino acid sequence of the new protein contained most of the characteristic elements of β-fructofuranosidases included in the family 32 of the glycosyl hydrolases (GH32). The heterologous yeast produced a protein of about 170 kDa, where N-linked and O-linked carbohydrates constituted about 15% and 38% of the total protein mass, respectively. Biochemical and kinetic properties of the heterologous protein were similar to the native enzyme, including its ability to produce prebiotic sugars. The maximum concentration of FOS obtained was 82.2 g/L, of which 6-kestose represented about 59% (w/w) of the total products synthesized. The potential of RdINV to fructosylate 19 hydroxylated compounds was also explored, of which eight sugars and four alditols were modified. The flexibility to recognize diverse fructosyl acceptors makes this protein valuable to produce novel glycosyl-compounds with potential applications in food and pharmaceutical industries.

Production, characterization, and immobilization of protease from the yeast Rhodotorula oryzicola

The protease was produced extracellularly in submerged fermentation by the yeast Rhodotorula oryzicola using different sources of nitrogen and maximum activity (6.54 × 10^-3 U/mg) was obtained in medium containing 2% casein (w/v). Purification of the protease by gel filtration chromatography resulted in a 3.07-fold increase of specific protease activity. The optimal pH and temperature for enzyme activity were 6.51 and 63.04 °C, respectively. Incubation in the presence of some salts enhanced enzyme activity, which peaked under 0.01 M BaCl₂ . The enzyme retained about 90% of enzymatic activity at temperatures 50-60 °C. The commercially available enzyme carriers evaluated, silica gel, Celite 545, and chitosan effectively immobilized the protease. The enzyme immobilized in Celite 545 retained 73.53% of the initial activity after 15 reuse cycles. These results are quite promising for large-scale production and immobilization of protease from R. oryzicola, as the high operational stability of the immobilized enzyme lowers production costs in biotechnological applications that require high enzymatic activity and stability under high temperatures.