Department for Innovation in Biological, Agro-food and Forest Systems (DIBAF), University of Tuscia, Via S. Camillo De Lellis snc, 01100, Viterbo, Italy.
Appl Microbiol Biotechnol. 2020 May;104(10):4617-4628. doi: 10.1007/s00253-020-10579-y. Epub 2020 Mar 31.
Orange peel waste (OPW), the primary byproduct of the juice extraction process, is annually generated in massive amounts (21 Mton), and its aqueous extraction in biorefining operations yields a liquid fraction, referred to as orange peel extract (OPE). Although OPE contains significant amounts of easily assimilable carbohydrates, such as fructose, glucose, and sucrose, no investigations have been conducted yet to assess its possible use in biodiesel production by oleaginous yeasts. Consequently, the objective of the present study was to assess whether OPE might act as the basis of a liquid medium for microbial lipid production. A screening conducted with 18 strains of oleaginous yeasts in shaken flask on the OPE-based medium showed that Rhodosporidium toruloides NRRL 1091 and Cryptococcus laurentii UCD 68-201 gave the best results in terms of lipid production (5.8 and 4.5 g L, respectively) and accumulation (77 and 47% on a dry matter basis, respectively). The subsequent scale transfer of the process to a 3-L STR operated in batch mode halved the time required to reach the lipid peak with the ensuing increase in volumetric productivities in R. toruloides NRRL 1091 (3646 mg L day) and C. laurentii UCD 68-201 (2970.7 mg L day). The biodiesel yields from the lipids of the former and the latter strain were 36.9 and 31.9%, respectively. Based on multivariate analysis of fatty acid methyl ester compositions, the lipids from the former and the latter strain were highly resembling those of Jatropha and palm oils, two commonly used feedstocks for biodiesel manufacturing.
橙皮废料（OPW）是榨汁过程中的主要副产物，每年的产量巨大（2100 万吨），在生物炼制过程中用水提取可得到液体部分，称为橙皮提取物（OPE）。尽管 OPE 含有大量易被吸收的碳水化合物，如果糖、葡萄糖和蔗糖，但尚未有研究评估其在油脂酵母生产生物柴油方面的可能用途。因此，本研究的目的是评估 OPE 是否可用作微生物油脂生产的液体培养基基础。利用摇瓶对 18 株油脂酵母在 OPE 基培养基上进行筛选，结果表明，红色拟内孢霉 NRRL 1091 和毕赤酵母 UCD 68-201 在油脂产量（分别为 5.8 和 4.5 g/L）和积累（分别为 77%和 47%干物质基础）方面表现最佳。随后，将该工艺转移到 3-L STR 中进行分批操作，将达到油脂峰值所需的时间缩短了一半，同时红色拟内孢霉 NRRL 1091（3646 mg/L/d）和毕赤酵母 UCD 68-201（2970.7 mg/L/d）的容积产率也相应增加。前一株和后一株菌的油脂的生物柴油产率分别为 36.9%和 31.9%。根据脂肪酸甲酯组成的多元分析，前一株和后一株菌的油脂与两种常用的生物柴油制造原料——麻疯树和棕榈油的油脂高度相似。
