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Caldicellulosiruptor bescii, the most thermophilic cellulolytic bacterium, is rich in hydrolytic and accessory enzymes that can degrade untreated biomass, but the precise role of many these enzymes is unknown. One of such enzymes is a predicted GDSL lipase or esterase encoded by the locus Athe_0553. In this study, this probable esterase named as Cbes-AcXE2 was overexpressed in Escherichia coli. The Ni-NTA affinity purified enzyme exhibited an optimum pH of 7.5 at an optimum temperature of 70 °C. Cbes-AcXE2 hydrolyzed p-nitrophenyl (pNP) acetate, pNP-butyrate, and phenyl acetate with approximately equal efficiency. The specific activity and K for the most preferred substrate, phenyl acetate, were 142 U/mg and 0.85 mM, respectively. Cbes-AcXE2 removed the acetyl group of xylobiose hexaacetate and glucose pentaacetate like an acetyl xylan esterase (AcXE). Bioinformatics analyses suggested that Cbes-AcXE2, which carries an SGNH hydrolase-type esterase domain, is a member of an unclassified carbohydrate esterase (CE) family. Moreover, Cbes-AcXE2 is evolutionarily and biochemically similar to an unclassified AcXE, Axe2, of Geobacillus stearothermophilus. Thus, we proposed a novel family of carbohydrate esterase for both Cbes-AcXE2 and Axe2.

Background Recent trends in bioprocessing have underlined the significance of lignocellulosic biomass conversions for biofuel production. These conversions demand at least 90% energy upgradation of cellulosic sugars to generate renewable drop-in biofuel precursors (Heff/C ~ 2). Chemical methods fail to achieve this without substantial loss of carbon; whereas, oleaginous biological systems propose a greener upgradation route by producing oil from sugars with 30% theoretical yields. However, these oleaginous systems cannot compete with the commercial volumes of vegetable oils in terms of overall oil yields and productivities. One of the significant challenges in the commercial exploitation of these microbial oils lies in the inefficient recovery of the produced oil. This issue has been addressed using highly selective oil capturing agents (OCA), which allow a concomitant microbial oil production and in situ oil recovery process. Results Adsorbent-based oil capturing agents were employed for simultaneous in situ oil recovery in the fermentative production broths. Yarrowia lipolytica, a model oleaginous yeast, was milked incessantly for oil production over 380 h in a media comprising of glucose as a sole carbon and nutrient source. This was achieved by continuous online capture of extracellular oil from the aqueous media and also the cell surface, by fluidizing the fermentation broth over an adsorbent bed of oil capturing agents (OCA). A consistent oil yield of 0.33 g per g of glucose consumed, corresponding to theoretical oil yield over glucose, was achieved using this approach. While the incorporation of the OCA increased the oil content up to 89% with complete substrate consumptions, it also caused an overall process integration. Conclusion The nondisruptive oil capture mediated by an OCA helped in accomplishing a trade-off between microbial oil production and its recovery. This strategy helped in realizing theoretically efficient sugar-to-oil bioconversions in a continuous production process. The process, therefore, endorses a sustainable production of molecular drop-in equivalents through oleaginous yeasts, representing as an absolute microbial oil factory.

L-ascorbyl palmitate (ASP) is an oil-soluble derivative of ascorbic acid which is used extensively in food, cosmetics industry, and medical hygiene. Enzymatic synthesis of ascorbyl palmitate in tert-butyl alcohol was carried out using indigenously immobilized lipase preparation PyCal with ascorbic acid and palmitic acid as starting material. The developed batch process under optimized reaction conditions resulted in conversion of 90% with relatively shorter reaction time of 6 h. Continuous process in packed bed reactor gave conversion of 50% with space time yield of 15.46 g/L/h which was found to be higher than the reported literature on enzymatic synthesis of ascorbyl palmitate. The immobilized lipase used in the present work showed good reusability. Characterization of formed ascorbyl palmitate was carried out by FTIR, MS/MS, H-NMR, and C-NMR. The enzymatic process resulted in selective synthesis of 6-O-L-ascorbyl palmitate with purity of 98.6% and no side product formation. The use of underivatized starting materials, high space time yield of 15.46 g L h, high recyclability of catalyst, and no by-product formation make the overall process highly efficient and clean in terms of energy consumption and waste generation, respectively. The optimized reaction parameters for ascorbyl palmitate synthesis in the present study can be used as a useful reference for industrial synthesis of fatty acid esters of ascorbic acid by enzymatic route.

The replacement of fossil carbon with biomass is currently crucial for ecological, environmental, and economic reasons. Although the use of biomass-derived eco-friendly products is appealing to the public and to industry, research is slow to meet the demand for it. This may be due to lack of awareness and cooperation among different sectors of science and stakeholders. This paper takes a holistic perspective. It discusses the importance of agro-waste as a biomass resource and provides suggestions for its effective utilization to make economical and eco-friendly products. Taking an interdisciplinary approach, it discusses the opportunities for direct, economical, and environmentally friendly research fields such as the modification of plant structure, increasing biomass yield, and conversion of agro-waste to materials and chemicals. It suggests how these various fields can benefit industry and the public, and also discusses the importance of dialogue between the different stakeholders to accelerate growth in innovation, implementation, and development.

Polyricinoleic acid (PRA) is a biodegradable polymer of ricinoleic acid, a hydroxy fatty acid present in castor oil. Depending upon the chain length, this homopolymer finds varied applications in oleochemical and allied industries. In the current research, we have first demonstrated synthesis route for PRA using Tin (II) 2-ethylhexanoate as a catalyst. The multiple operational variables such as the effect of the reaction time, temperature, catalyst loading, water condensation and recuperation of polymer were studied systemically. Under the optimized conditions, PRA with a molecular weight of ∼4kD was synthesized at 150 °C within 14 hrs. Using solvent extraction, the unreacted monomer and catalyst were recycled back to the next round of polymerization. The final PRA product was characterized as a single molecule with superior functional properties and suggesting to its use as an environmentally friendly biopolymer.

HighlightsSynthesis of modified fats by enzymatic acidolysis of fully hydrogenated soybean oil with caprylic acid.Indigenously immobilized sn 1,3 specific lipase used as catalyst.Production of modified fats in shortened reaction time.Significant change in the physico-chemical properties of newly formed product as observed using DSC and XRD analysis.Synthesized product has potential to be used in formulation of functional foods.