Browsing by Author "Castro, Eulogio"
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Item Open Access Fermentative valorisation of xylose-rich hemicellulosic hydrolysates from agricultural waste residues for lactic acid production under non-sterile conditions(Elsevier, 2023-05-18) Cox, Rylan; Narisetty, Vivek; Castro, Eulogio; Agrawal, Deepti; Jacob, Samuel; Kumar, Gopalakrishnan; Kumar, Deepak; Kumar, VinodLactic acid (LA) is a platform chemical with diverse industrial applications. Presently, commercial production of LA is dominated by microbial fermentation using sugary or starch-based feedstocks. Research pursuits emphasizing towards sustainable production of LA using non-edible and renewable feedstocks have accelerated the use of lignocellulosic biomass (LCB). The present study focuses on the valorisation of xylose derived from sugarcane bagasse (SCB) and olive pits (OP) through hydrothermal and dilute acid pretreatment, respectively. The xylose-rich hydrolysate obtained was used for LA production by homo-fermentative and thermophilic Bacillus coagulans DSM2314 strain under non-sterile conditions. The fed-batch mode of fermentation resulted in maximum LA titers of 97.8, 52.4 and 61.3 g/L with a yield of 0.77, 0.66 and 0.71 g/g using pure xylose, xylose-rich SCB and OP hydrolysates, respectively. Further, a two-step aqueous two-phase system (ATPS) extraction technique was employed for the separation and recovery of LA accumulated on pure and crude xylose. The LA recovery was 45 – 65% in the first step and enhanced to 80–90% in the second step.The study demonstrated an efficient integrated biorefinery approach to valorising the xylose-rich stream for cost-effective LA production and recovery.Item Open Access High level xylitol production by Pichia fermentans using non-detoxified xylose-rich sugarcane bagasse and olive pits hydrolysates(Elsevier, 2021-09-22) Narisetty, Vivek; Castro, Eulogio; Durgapal, Sumit; Coulon, Frederic; Jacob, Samuel; Kumar, Dinesh; Awasthi, Mukesh Kumar; Pant, Kamal Kishore; Parameswaran, Binod; Kumar, VinodHemicellulosic sugars, the overlooked fraction of lignocellulosic residues can serve as potential and cost-effective raw material that can be exploited for xylitol production. Xylitol is a top platform chemical with applications in food and pharmaceutical industries. Sugarcane bagasse (SCB) and olive pits (OP) are the major waste streams from sugar and olive oil industries, respectively. The current study evaluated the potential of Pichia fermentans for manufacturing of xylitol from SCB and OP hydrolysates through co-fermentation strategy. The highest xylitol accumulation was noticed with a glucose and xylose ratio of 1:10 followed by feeding with xylose alone. The fed-batch cultivation using pure xylose, SCB, and OP hydrolysates, resulted in xylitol accumulation of 102.5, 86.6 and 71.9 g/L with conversion yield of 0.78, 0.75 and 0.74 g/g, respectively. The non-pathogenic behaviour and ability to accumulate high xylitol levels from agro-industrial residues demonstrates the potential of P. fermentans as microbial cell factory.Item Open Access Process optimisation for production and recovery of succinic acid using xylose-rich hydrolysates by Actinobacillus succinogenes(Elsevier, 2021-10-28) Jokodola, Esther Oreoluwa; Narisetty, Vivek; Castro, Eulogio; Durgapal, Sumit; Coulon, Frederic; Sindhu, Raveendran; Binod, Parameswaran; Banu, J. Rajesh; Kumar, Gopalakrishnan; Kumar, VinodSuccinic acid (SA) is a top platform chemical obtainable from biomass. The current study evaluated the potential of Actinobacillus succinogenes for SA production using xylose-rich hemicellulosic fractions of two important lignocellulosic feedstocks, olive pits (OP) and sugarcane bagasse (SCB) and the results were compared with pure xylose. Initial experiments were conducted in shake flask followed by batch and fed-batch cultivation in bioreactor. Further separation of SA from the fermented broth was carried out by adapting direct crystallisation method. During fed-batch culture, maximum SA titers of 36.7, 33.6, and 28.7 g/L was achieved on pure xylose, OP and SCB hydrolysates, respectively, with same conversion yield of 0.27 g/g. The recovery yield of SA accumulated on pure xylose, OP and SCB hydrolysates was 79.1, 76.5, and 75.2%, respectively. The results obtained are of substantial value and pave the way for development of sustainable SA biomanufacturing in an integrated biorefinery.