Browsing by Author "Chandel, Anuj Kumar"
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Item Open Access Biological production and recovery of 2,3-butanediol using arabinose from sugar beet pulp by Enterobacter ludwigii(Elsevier, 2022-04-21) Narisetty, Vivek; Narisetty, Sudheera; Jacob, Samuel; Kumar, Deepak; Leeke, Gary A.; Chandel, Anuj Kumar; Singh, Vijai; Srivastava, Vimal Chandra; Kumar, VinodSugar beet pulp (SBP) is a major byproduct from the sugar industries and consists of >20% w/w arabinose. The current work evaluated the potential of Enterobacter ludwigii assimilating pure arabinose and arabinose rich hydrolysate from SBP pellets for 2,3-butanediol (BDO) production. The hydrolysate was obtained through dilute acid pretreatment (DAP) with sulphuric acid. The process was optimized for acid and solid loading to obtain a hydrolysate free from furan derivatives. The effect of different levels of substrate (10–60 g/L) using pure arabinose was conducted in shake flask experiments, followed by co-fermentation with small amounts of glucose and SBP hydrolysate. After flask cultivations, BDO fermentations were carried-out in a bench-top bioreactor in batch and fed-batch modes using pure arabinose as well as SBP hydrolysate. The fed-batch culture led to BDO production of 42.9 and 35.5 g/L from pure arabinose and SBP hydrolysate with conversion yields of 0.31 and 0.29 g/g, respectively. Finally, BDO accumulated on pure arabinose and SBP hydrolysate were recovered using an aqueous two-phase extraction system. The recovery yield of BDO accumulated on arabinose and hydrolysate was ∼97%. The work demonstrated the feasibility of using SBP as a suitable feedstock for manufacturing BDO.Item Open Access Bioprocessing of fermentable sugars derived from water hyacinth into microbial lipids and single cell proteins by oleaginous yeast Rhodosporidium toruloides NCIM 3547(Springer, 2021-10-09) Alankar, Senthilnathan Sri Laxma; Sajesh, Nithianandam; Rastogi, Shrestha; Sakhuja, Simar; Rajeswari, Gunasekaran; Kumar, Vinod; Chandel, Anuj Kumar; Jacob, SamuelIn this study, we employed microwave-acid pretreatment for water hyacinth (WH) to obtain liquid hydrolysate that contains sugars derived from holocellulosic components of biomass for further oleaginous yeast fermentation. In order to remove the inhibitors such as furans after acid treatment, detoxification of hydrolysate was done and we compared the efficiency of this step with non-detoxified hydrolysate towards capability of the Rhodosporidium toruloides NCIM 3547 (an oleaginous yeast) to produce microbial lipid and single cell protein. The results indicated that the reducing sugar concentration was found to be higher in non-detoxified hydrolysate (65.41 g/L) than detoxified one (59.18 g/L). When the non-detoxified liquid hydrolysate was supplemented with yeast extract as a complex organic source for R. toruloides, resulted in a maximum lipid yield of about 0.813 ± 0.041 (g/g) and 53.60 ± 2.68 (g/g) of single cell protein content with 0.038 g/L/d of protein productivity. Two kinetic models, hybrid Logistic-Monod and Luedeking-Piret, were employed to assess the microbial growth and the substrate utilization that were found to be in well agreement with the experimental data with a coefficient of determination (R2) value ranging from 0.95 to 0.99 thereby demonstrating the efficiency of the hydrolysate supplemented media. Furthermore, GC-MS analysis of transesterified lipids revealed the presence of various FAME (fatty acid methyl esters) and also the presence of increased levels of total saturated fatty acids (35.03%) advocates its high potential in biodiesel production. This study demonstrates the feasibility of sustainable valorization of WH-derived liquid hydrolysate towards a greener biorefinery framework.Item Open Access Enhanced 2,3-Butanediol production by mutant Enterobacter ludwigii using Brewers’ spent grain hydrolysate: process optimization for a pragmatic biorefinery loom(Elsevier, 2021-06-18) Amraoui, Yassin; Prabhu, Ashish A.; Narisetty, Vivek; Coulon, Frederic; Chandel, Anuj Kumar; Willoughby, Nicholas; Jacob, Samuel; Koutinas, Apostolis; Kumar, Vinod2,3-Butanediol (BDO) is a fossil-based versatile bulk chemical with a multitude of applications. BDO can also be synthesized using microbial cell factories harnessing renewable feedstocks. However, the high cost of the substrate via microbial route impedes commercial manufacturing of BDO. Therefore, identification of cheaper substrates could make bio-based BDO production more cost-competitive. Brewers’ spent grain (BSG), a major by-product of breweries, is an inexpensive source of fermentable sugars and proteins. In the present study, we have attempted the bioproduction of BDO by Enterobacter ludwigii using BSG as feedstock. A random E. ludwigii mutant obtained after treatment with ethyl methane sulfonate (EMS) resulted in a BDO titer (9.5 g/L), ~30% higher in comparison to the wild type strain with a yield of 0.48 gBDO/gGlucose approaching the theoretical yield of 0.50 gBDO/gGlucose. The enzymatic hydrolysis of microwave-assisted alkali pretreated BSG was optimized using the statistical Taguchi design. The BSG hydrolysis under optimal conditions (pH: 6.0; temperature: 50 °C; BSG: 10% w/v; enzyme loading: 2% v/v) resulted in a glucose yield of 0.25 gGlucose/gBiomass. The uncontrolled pH was found to be more beneficial for BDO accumulation from BSG hydrolysate in batch bioreactor cultivation as compared with controlled one. The fed-batch cultivation with forced pH fluctuations at an aeration rate of 2.0 vvm resulted in BDO accumulation of 118.5 g/L from glucose-rich BSG hydrolysate with the yield and productivity of 0.43 g/g and 1.65 g/L.h, respectively. To the best of our knowledge, this is the first study on BDO production from BSG.Item Open Access Integrated fermentative production and downstream processing of 2,3-butanediol from sugarcane bagasse-derived xylose by mutant strain of Enterobacter ludwigii(American Chemical Society, 2021-07-16) Amraoui, Yassin; Narisetty, Vivek; Coulon, Frederic; Agrawal, Deepti; Chandel, Anuj Kumar; Maina, Sofia; Koutinas, Apostolis; Kumar, VinodIn this study, a mutant strain of Enterobacter ludwigii developed in our previous work, was evaluated to utilize pure xylose as the sole carbon and energy source for 2,3-butanediol (BDO) production. Later, this strain was also investigated on detoxified and nondetoxified xylose-rich hydrolysate obtained from hydrothermally pretreated sugarcane bagasse (SCB) for BDO production. Supplementing the fermentation medium with 0.2% w/v yeast extract improved cell growth (31%), BDO titer (43%), and yield (41%) against the synthetic medium devoid of any complex nitrogen source. The fed-batch culture with cyclic control of pH resulted in a BDO production of 71.1 g/L from pure xylose with overall yield and productivity of 0.40 g/g and 0.94 g/L·h, respectively. While BDO titer, yield, and productivity of 63.5 g/L, 0.36 g/g, and 0.84 g/L·h, were acheived with detoxified hydrolysate, respectively. In contrast, 32.7 g/L BDO was produced from nondetoxified hydrolysate with a conversion yield of 0.33 g/g and a productivity of 0.43 g/L·h. BDO accumulated on pure xylose and detoxified SCB hydrolysate was separated by aqueous two-phase system (ATPS) method using (NH4)2SO4 as salting-out agent and isopropanol as an extractant, resulting in the BDO recovery of more than 85%. The results achieved in the current work exemplify a step toward industrial BDO production from cost-effective hemicellulosic hydrolysates by E. ludwigii.