Tsakona Sofia, Papadaki Aikaterini, Kopsahelis Nikolaos, Kachrimanidou Vasiliki, Papanikolaou Seraphim, Koutinas Apostolis
Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
Department of Food Science and Technology, Ionian University, 28100 Argostoli, Greece.
Foods. 2019 Jul 31;8(8):300. doi: 10.3390/foods8080300.
Diversified mixed confectionery waste streams were utilized in a two-stage bioprocess to formulate a nutrient-rich fermentation media for microbial oil production. Solid-state fermentation was conducted for the production of crude enzyme consortia to be subsequently applied in hydrolytic reactions to break down starch, disaccharides, and proteins into monosaccharides, amino acids, and peptides. Crude hydrolysates were evaluated in bioconversion processes using the red yeast DSM 4444 both in batch and fed-batch mode. Under nitrogen-limiting conditions, during fed-batch cultures, the concentration of microbial lipids reached 16.6-17 g·L with the intracellular content being more than 40% (w/w) in both hydrolysates applied. . was able to metabolize mixed carbon sources without catabolite repression. The fatty acid profile of the produced lipids was altered based on the substrate employed in the bioconversion process. Microbial lipids were rich in polyunsaturated fatty acids, with oleic acid being the major fatty acid (61.7%, w/w). This study showed that mixed food side-streams could be valorized for the production of microbial oil with high unsaturation degree, pointing towards the potential to produce tailor-made lipids for specific food applications. Likewise, the proposed process conforms unequivocally to the principles of the circular economy, as the entire quantity of confectionery by-products are implemented to generate added-value compounds that will find applications in the same original industry, thus closing the loop.
多样化的混合糖果废物流在两阶段生物过程中被利用，以配制用于微生物油脂生产的富含营养的发酵培养基。进行固态发酵以生产粗酶复合物，随后将其应用于水解反应，将淀粉、二糖和蛋白质分解为单糖、氨基酸和肽。使用红酵母DSM 4444在分批和补料分批模式下对粗水解产物进行生物转化过程评估。在氮限制条件下，在补料分批培养期间，微生物脂质浓度达到16.6 - 17 g·L，在所应用的两种水解产物中细胞内含量均超过40%（w/w）。能够代谢混合碳源而不受分解代谢物阻遏。所产生脂质的脂肪酸谱根据生物转化过程中使用的底物而改变。微生物脂质富含多不饱和脂肪酸，油酸是主要脂肪酸（61.7%，w/w）。本研究表明，混合食品副产物可用于生产高不饱和度的微生物油脂，这表明有可能生产用于特定食品应用的定制脂质。同样，所提出的工艺明确符合循环经济原则，因为全部糖果副产品都被用于生成将在同一原始行业中找到应用的增值化合物，从而实现循环。
