Biodiesel Production From Lignocellulosic Biomass Using Oleaginous Microbes: Prospects for Integrated Biofuel Production.

Biodiesel is an eco-friendly, renewable, and potential liquid biofuel mitigating greenhouse gas emissions. Biodiesel has been produced initially from vegetable oils, non-edible oils, and waste oils. However, these feedstocks have several disadvantages such as requirement of land and labor and remain expensive. Similarly, in reference to waste oils, the feedstock content is succinct in supply and unable to meet the demand. Recent studies demonstrated utilization of lignocellulosic substrates for biodiesel production using oleaginous microorganisms. These microbes accumulate higher lipid content under stress conditions, whose lipid composition is similar to vegetable oils. In this paper, feedstocks used for biodiesel production such as vegetable oils, non-edible oils, oleaginous microalgae, fungi, yeast, and bacteria have been illustrated. Thereafter, steps enumerated in biodiesel production from lignocellulosic substrates through pretreatment, saccharification and oleaginous microbe-mediated fermentation, lipid extraction, transesterification, and purification of biodiesel are discussed. Besides, the importance of metabolic engineering in ensuring biofuels and biorefinery and a brief note on integration of liquid biofuels have been included that have significant importance in terms of circular economy aspects.

ALBA: A comprehensive growth model to optimize algae-bacteria wastewater treatment in raceway ponds.

This paper proposes a new model describing the algae-bacteria ecosystem evolution in an outdoor raceway for wastewater treatment. The ALBA model is based on mass balances of COD, C, N and P, but also H and O. It describes growth and interactions among algae, heterotrophic and nitrifying bacteria, while local climate drives light and temperature. Relevant chemical/physical processes are also included. The minimum-law was used as ground principle to describe the multi-limitation kinetics. The model was set-up and calibrated with an original data set recorded on a 56 m2 raceway located in the South of France, continuously treating synthetic wastewater. The main process variables were daily measured along 443 days of operations and dissolved O2 and pH were on-line recorded. A sub-dataset was used for calibration and the model was successfully validated, along the different seasons over a period of 414 days. The model proved to be effective in reproducing both the short term nycthemeral dynamics and the long-term seasonal ones. The analysis of different scenarios reveals the fate of nitrogen and the key role played by oxygen and CO2 in the interactions between the different players of the ecosystem. On average, the process turns out to be CO2 neutral, as compared to a standard activated sludge where approximately half of the influent carbon will end up in the atmosphere. The ALBA model revealed that a suboptimal regulation of the paddle wheel can bring to several detrimental impacts. At high velocity, the strong aeration will reduce the available oxygen provided by photo-oxygenation, while very low aeration can rapidly lead to oxygen inhibition of the photosynthetic process. On the other hand, during night, the paddle wheel is fundamental to ensure enough oxygen in the system to support algal-bacteria respiration. The model can be used to support advanced control strategies, including smart regulation of the paddle wheel velocity to more efficiently balance the mixing, aeration and degassing effects.

A Summer Mortality Outbreak of Lactococcosis by Lactococcus garvieae in a Raceway System Affecting Farmed Rainbow Trout (Oncorhynchus mykiss) and Brook Trout (Salvelinus fontinalis).

Lactococcosis is a fish disease of major concern in Mediterranean countries caused by Lactococcus garvieae. The most susceptible species is the rainbow trout (Oncorhynchus mykiss), suffering acute disease associated with elevated mortalities compared to other fish species. References reported that other salmonids are also susceptible to the disease, but no mortality outbreak has been described to date. The aim of this study was to present a mortality outbreak that occurred in brook trout (Salvelinus fontinalis) farmed in northwestern Italy during the summer of 2018. Fish exhibited clinical signs, such as exophthalmos, diffused hemorrhages localized in the ocular zone, hemorrhagic enteritis, and enlarged spleen. L. garvieae was isolated in all fish. Molecular and epidemiological characterization of the isolates, through Pulsed Field Gel Electrophoresis (PFGE), confirmed the initial hypothesis of water as vehicle of infection favoring transmission between rainbow trout farmed in upstream compartments and brook trout located in downstream tanks. Moreover, several environmental conditions affected and promoted the outbreak, among them the high-water temperature, which probably induced a physiological stress in brook trout, being way above the optimal temperature for this species, increasing the susceptibility to infection.

Hernia of the swim bladder (aerocystocele) with concurrent mycotic granulomatous inflammation and swim bladder carcinoma in a wild mullet (Mugil cephalus).

We describe a hernia of the swim bladder, with a concurrent mycotic granulomatous inflammation, and carcinoma of the swim bladder in a wild mullet (Mugil cephalus) referred for an exophytic dorsal mass. Grossly, the mass was white, soft, and composed of multiple cystic gas-containing chambers connected by a funnel-shaped tissue segment to the coelomic swim bladder. Histologically, the mass was characterized by cysts of variable size, multifocally contiguous with the subepithelial rete mirabile, supported by abundant fibrous tissue. The skin covering the herniated swim bladder was focally ulcerated and replaced by abundant granulation tissue in which multiple scattered granulomas centered on pigmented fungal hyphae were observed. These granulomas were also seen in the remaining coelomic portion of the swim bladder as well as in the spleen, perivisceral pancreas, and peritoneal adipose tissue; the fungus was molecularly identified as Cladosporium spp. Focally, arising from the herniated swim bladder epithelium, an unencapsulated poorly demarcated, moderately cellular neoplasm, composed of islands, lobules, and acini of neoplastic epithelium, was found.