Enhanced microbial oil production by activated sludge microorganisms via co‐fermentation of glucose and xylose

Abstract

The co-fermentation of glucose and xylose by activated sludge microorganisms for the production of microbial oils for use as biodiesel feedstock was investigated. Various carbon sources at initial concentration of 60 g/L and C:N ratio 70:1 were investigated: xylose, glucose, and 2:1 and 1:2 (by mass) glucose/xylose mixtures. Oil accumulation ranged between 12 to 22% CDW, the highest of which was obtained when xylose was the sole substrate used. Kinetic modeling of the fermentation data showed that specific growth and oil accumulation rates were similar in all substrate types and the lipid coefficient ranged from 0.02 to 0.06 g/g of sugar consumed. The fatty acid methyl ester yield and composition of the lipids showed their suitability for conversion to biodiesel. Based on the results, lignocellulose sugars could be used as fermentation substrates by activated sludge microorganisms for enhancing the oil content of sewage sludge for its use as a sustainable biofuel feedstock source.

Effect of pH on biodiesel production and the microbial structure of glucose-fed activated sludge

“…It is necessary to increase the lipid content and biodiesel yield to make it more competitive. A number of factors, such as the type of organic substrate, the organic loading rate, and the ratio of carbon to nitrogen (C:N), influenced the biodiesel production of activated sludge (Mondala et al, 2012(Mondala et al, , 2013. Operational adjustments can be made to create a more favorable environment for accumulation of lipid and production of biodiesel from activated sludge.…”

Lipids from Wastewater‐Activated Sludge Cultivated on Acetic Acid as Potential Alternatives to High‐Value Oils and Fats

“…Lipids from the microbial consortia of activated sludge (AS) generated by wastewater treatment plants (WWTP) have been successfully enhanced by aerobic cultivation on a high molar carbon to nitrogen ratio (C/N) using various carbon sources (Fortela et al, ,b; Mondala et al, ; Revellame et al, ; Yook et al, ). Initial studies used sugars as model carbon sources (Mondala et al, ) while recent studies showed that acetic acid can also be a suitable carbon source via fed‐batch cultivation, achieving up to 20% (w/w dry biomass) lipid content (Fortela et al, ). Acetic acid was proposed as an economical carbon source as it is a typical intermediate or by‐product of the anaerobic digestion of organic wastes (Yook et al, ).…”

Optimization and kinetic modeling of an enhanced bio-hydrogen fermentation with the addition of synergistic biochar and nickel nanoparticle

“…5 Apart from the direct water splitting via the semi-conductive photocatalyst that has attracted many interests in the past, 6 the bio-hydrogen process still remains competitive because of its many appealing advantages, ie, cost-effectiveness, simplicity in operations, independence of solar radiation, and highly efficient utilization of renewable lignocellulose. [7][8][9][10] Although efforts of investigating dark hydrogen fermentation have been made for a few decades, there are still quite many spaces left for the optimization of the entire process in the aspect of maximizing the hydrogen yield, minimizing the secondary metabolites inhabitations, and maintaining the stability of the microbes during fermentation. 11,12 In order to enhance the hydrogen yield, different efforts have been trialed by many scholars.…”