CFD evaluation of hydrophobic feedstock bench-scale fermenters for efficient high agitation volumetric mass transfer.

A new biomanufacturing platform combining intracellular metabolic engineering of the oleaginous yeast Yarrowia lipolytica and extracellular bioreaction engineering provides efficient bioconversion of plant oils/animal fats into high-value products. However, predicting the hydrodynamics and mass transfer parameters is difficult due to the high agitation and sparging required to create dispersed oil droplets in an aqueous medium for efficient yeast fermentation. In the current study, commercial computational fluid dynamic (CFD) solver Ansys CFX coupled with the MUSIG model first predicts two-phase system (oil/water and air/water) mixing dynamics and their particle size distributions. Then, a three-phase model (oil, air, and water) utilizing dispersed air bubbles and a polydispersed oil phase was implemented to explore fermenter mixing, gas dispersion efficiency, and volumetric mass transfer coefficient estimations (kL a). The study analyzed the effect of the impeller type, agitation speed, and power input on the tank's flow field and revealed that upward-pumping pitched blade impellers (PBI) in the top two positions (compared to Rushton-type) provided advantageous oil phase homogeneity and similar estimated kL a values with reduced power. These results show good agreement with the experimental mixing and kL a data.

Using oils and fats to replace sugars as feedstocks for biomanufacturing: Challenges and opportunities for the yeast Yarrowia lipolytica.

More than 200 million tons of plant oils and animal fats are produced annually worldwide from oil, crops, and the rendered animal fat industry. Triacylglycerol, an abundant energy-dense compound, is the major form of lipid in oils and fats. While oils or fats are very important raw materials and functional ingredients for food or related products, a significant portion is currently diverted to or recovered as waste. To significantly increase the value of waste oils or fats and expand their applications with a minimal environmental footprint, microbial biomanufacturing is presented as an effective strategy for adding value. Though both bacteria and yeast can be engineered to use oils or fats as the biomanufacturing feedstocks, the yeast Yarrowia lipolytica is presented as one of the most attractive platforms. Y. lipolytica is oleaginous, generally regarded as safe, demonstrated as a promising industrial producer, and has unique capabilities for efficient catabolism and bioconversion of lipid substrates. This review summarizes the major challenges and opportunities for Y. lipolytica as a new biomanufacturing platform for the production of value-added products from oils and fats. This review also discusses relevant cellular and metabolic engineering strategies such as fatty acid transport, fatty acid catabolism and bioconversion, redox balances and energy yield, cell morphology and stress response, and bioreaction engineering. Finally, this review highlights specific product classes including long-chain diacids, wax esters, terpenes, and carotenoids with unique synthesis opportunities from oils and fats in Y. lipolytica.

Assessment of surface water quality in Lushan: a world heritage sites in China.

Surface water is one of the important landscape resources in tourist attractions. Due to tourism activities, the surface water quality (SWQ) in scenic was often damaged. An example of the Lushan Scenic, the SWQ, was analyzed and evaluated by water sampling and laboratory analysis methods. The results explained that the SWQ of Lushan Scenic was seriously damaged. The comprehensive index explained that the SWQ of seven sampling dots was from mild pollution to extreme pollution. The main pollutants were ammonia nitrogen, total nitrogen, and total phosphorus, and the TN and TP were the most serious. According to the data of tourists in 2017, the emergency water capacity stored by reservoirs was 32.5 days if there was no raining in Lushan Scenic. The main factors affecting the SWQ were tourism activities, such as tourists, hotels, restaurants, and other commercial activities, and pollutants discharged from domestic water were not completely treated in Lushan Scenic.

Treatment of varicocele with Fu's subcutaneous needling: A case report.

RATIONALE: Fu's subcutaneous needling (FSN) is an innovative therapy of traditional acupuncture. FSN has been widely applied for the treatment of pain symptoms by relieving local muscle tension and promoting local blood circulation. Varicocele (VCL) is a disease that commonly occurs in male adolescents. Patients with VCL can suffer from pain in the scrotum, inguinal area, or unilateral testis, which could be an indication for FSN. In this study, we present a unique case, in which a 30-year-old male patient with VCL benefitted from FSN. PATIENT CONCERNS: A 30-year-old male complained of dull pain and swelling in the testicular area for 4 months. No significant abnormalities were identified in his genitalia by physical examination. DIAGNOSES: The patient was diagnosed with VCL, with his symptoms and signs of dull pain and swelling in the testicular area, and ultrasound also demonstrated the left-side VCL. INTERVENTIONS: FSN was performed successfully twice a week on a different day without postoperative complications. The total course lasted 8 weeks. OUTCOMES: The patient experienced obvious relief of his testicular pain and swelling after each treatment course. All his symptoms resolved and disappeared after 4 treatment courses. After the 8-week treatment course, the color ultrasound after treatment demonstrated improved anastomotic blood flow rates in his left spermatic vein. No narrow or thrombotic parts were observed post-treatment compared to the color ultrasound before treatment. The patient was followed up at 1, 3, and 6 months after treatment. During the follow-up period, his previous symptoms disappeared without recurrence. LESSONS: FSN significantly improved the patent's symptoms of testicular pain and abnormal dilatation and tortuosity of the spermatic veins. FSN might exert its therapeutic effect by improving the relaxation of muscle oppression and increasing the local blood reperfusion to resume blood stream. Due to the limitation of a single clinical observation case, a randomized clinical trial with a sufficient follow-up time is needed.

Treatment of poststroke constipation with moxibustion: A case report.

RATIONALE: Moxibustion, an important therapeutic measure of TCM, can stimulate acupoints to unblock the meridians and collaterals, regulate the function of qi and blood, support health, and expel pathogens. So it could be an effective and safe for the treatment of constipation and improvement of the quality of life in poststroke patients with constipation. PATIENT CONCERNS: He has a history of constipation, with the defecation of hard, bound stool every 2 to 3 days with the help of glycerin enema. DIAGNOSES: Constipation for >6 months; Cerebral infarction for 9 months; Type 2 diabetes for 3 years. Hypertension for approximately 1 month. INTERVENTIONS: From the fifth day after admission, 5 rounds of moxibustion with moxa cones were administered at the bilateral ST25 and CV6 acupoints. OUTCOMES: The patient successfully defecated within 1hour. Subsequently, the patient could maintain daily unobstructed defecation with a normal total stool weight and moderate hardness. LESSONS: Moxibustion is effective and safe for the treatment of constipation and improvement of the quality of life in post-stroke patients with constipation.

Integrating Cellular and Bioprocess Engineering in the Non-Conventional Yeast Yarrowia lipolytica for Biodiesel Production: A Review.

As one of the major biofuels to replace fossil fuel, biodiesel has now attracted more and more attention due to its advantages in higher energy density and overall less greenhouse gas generation. Biodiesel (fatty acid alkyl esters) is produced by chemically or enzymatically catalyzed transesterification of lipids from microbial cells, microalgae, oil crops, or animal fats. Currently, plant oils or waste cooking oils/fats remain the major source for biodiesel production via enzymatic route, but the production capacity is limited either by the uncertain supplement of plant oils or by the low or inconsistent quality of waste oils/fats. In the past decades, significant progresses have been made on synthesis of microalgae oils directly from CO2via a photosynthesis process, but the production cost from any current technologies is still too high to be commercialized due to microalgae's slow growth rate on CO2, inefficiency in photo-bioreactors, lack of efficient contamination control methods, and high cost in downstream recovery. At the same time, many oleaginous microorganisms have been studied to produce lipids via the fatty acid synthesis pathway under aerobic fermentation conditions, among them one of the most studied is the non-conventional yeast, Yarrowia lipolytica, which is able to produce fatty acids at very high titer, rate, and yield from various economical substrates. This review summarizes the recent research progresses in both cellular and bioprocess engineering in Y. lipolytica to produce lipids at a low cost that may lead to commercial-scale biodiesel production. Specific technologies include the strain engineering for using various substrates, metabolic engineering in high-yield lipid synthesis, cell morphology study for efficient substrate uptake and product formation, free fatty acid formation and secretion for improved downstream recovery, and fermentation engineering for higher productivities and less operating cost. To further improve the economics of the microbial oil-based biodiesel, production of lipid-related or -derived high-value products are also discussed.