http://localhost:8080/xmlui/handle/123456789/2068 2026-04-08T10:28:33Z 2026-04-08T10:28:33Z Christopher, M Anusree, M Mathew, A K Nampoothiri, K M Sukumaran, R K Pandey, A http://localhost:8080/xmlui/handle/123456789/4837 2024-04-05T10:07:42Z 2016-08-01T00:00:00Z

Detoxification of acidic biorefinery waste liquor for production of high value amino acid Christopher, M; Anusree, M; Mathew, A K; Nampoothiri, K M; Sukumaran, R K; Pandey, A The current study evaluates the detoxification of acid pretreatment liquor (APL) using adsorbent (ADS 400 & ADS 800) or ion-exchange (A-27MP & A-72MP) resins and its potential for amino acid production. The APL is generated as a by-product from the pretreatment of lignocellulosic biomass and is rich monomeric sugars as well as sugar degradation products (fermentation inhibitors) such as furfural and hydroxymethyl furfural (HMF). Of the four resins compared, ADS 800 removed approximately 85% and 60% of furfural and HMF, respectively. ADS 800 could be reused for up to six cycles after regeneration without losing its adsorption properties. The study was further extended by assessing the fermentability of detoxified APL for l-lysine production using wild and mutant strains of Corynebacterium glutamicum. The detoxified APL was superior to APL for l-lysine production.

2016-08-01T00:00:00Z Dhar, K S Wendisch, V F Nampoothiri, K M http://localhost:8080/xmlui/handle/123456789/4836 2024-04-05T10:07:22Z 2016-07-20T00:00:00Z

Engineering of Corynebacterium glutamicum for xylitol production from lignocellulosic pentose sugars Dhar, K S; Wendisch, V F; Nampoothiri, K M Xylitol is a non-fermentable sugar alcohol used as sweetener. Corynebacterium glutamicum ATCC13032 was metabolically engineered for xylitol production from the lignocellulosic pentose sugars xylose and arabinose. Direct conversion of xylose to xylitol was achieved through the heterologous expression of NAD(P)H-dependent xylose reductase (xr) gene from Rhodotorula mucilaginosa. Xylitol synthesis from arabinose was attained through polycistronic expression of l-arabinose isomerase (araA), d-psicose 3 epimerase (dpe) and l-xylulose reductase (lxr) genes from Escherichia coli, Agrobacterium tumefaciens and Mycobacterium smegmatis, respectively. Expression of xr and the synthetic araA-dpe-lxr operon under the control of IPTG-inducible Ptac promoter enabled production of xylitol from both xylose and arabinose in the mineral (CGXII) medium with glucose as carbon source. Additional expression of a pentose transporter (araTF) gene enhanced xylitol production by about four-fold compared to the parent strain. The constructed strain Cg-ax3 produced 6.7 ± 0.4 g/L of xylitol in batch fermentations and 31 ± 0.5 g/L of xylitol in fed-batch fermentations with a specific productivity of 0.28 ± 0.05 g/g cdw/h. The strain Cg-ax3 was also validated for xylitol production from pentose rich, acid pre-treated liquor of sorghum stover (SAPL) and the results were comparable in both SAPL (27 ± 0.3 g/L) and mineral medium (31 ± 0.5 g/L).

2016-07-20T00:00:00Z Devendra, L P Kiran Kumar, M Pandey, A http://localhost:8080/xmlui/handle/123456789/4835 2024-04-05T10:06:53Z 2016-08-01T00:00:00Z

Evaluation of hydrotropic pretreatment on lignocellulosic biomass Devendra, L P; Kiran Kumar, M; Pandey, A The production of cellulosic ethanol from biomass is considered as a promising alternative to fossil fuels, providing a sustainable option for fuels production in an environmentally compatible manner. The presence of lignin poses a significant challenge for obtaining biofuels and bioproducts from biomass. Part of that problem involves understanding fundamental aspects of lignin structure which can provide a pathway for the development of improved technologies for biomass conversion. Hydrotropic pretreatment has several attractive features that make it an attractive alternative for biofuel production. This review highlights the recent developments on hydrotropic pretreatment processes for lignocellulosic biomass on a molecular structure basis for recalcitrance, with emphasis on lignin concerning chemical structure, transformation and recalcitrance. The review also evaluates the hydrotropic delignification in comparison to alkaline delignification on lignin reduction and surface coverage by lignin. The effect of hydrotrope pretreatment on enzymatic saccharification has also been discussed.

2016-08-01T00:00:00Z Ummalyma, S B Mathew, A K Pandey, A Sukumaran, R K http://localhost:8080/xmlui/handle/123456789/4834 2024-04-05T10:04:50Z 2016-08-01T00:00:00Z

Harvesting of microalgal biomass: Efficient method for flocculation through pH modulation Ummalyma, S B; Mathew, A K; Pandey, A; Sukumaran, R K Harvesting of the micro alga Chlorococcum sp. R-AP13 through autoflocculation, chemical flocculants or by change in medium pH was evaluated. Surface charge of algal cells changed in response to the method used and affected flocculation efficiency. While aluminum sulfate and FeCl3 supported 87% and 92% efficiency, auto flocculation could recover 75% of biomass in 10 min. Maximum efficiency (94%) was obtained with change in medium pH from 8.5 to 12.0 achieved through addition of 40 mg l−1 of NaOH. Since high concentrations of FeCl3 and AlSO4 were toxic to the cells, flocculation induced by pH change may be considered the most effective strategy. Residual medium after flocculation could be reused efficiently for algal cultivation, minimizing the demand for fresh water.

2016-08-01T00:00:00Z