Sampa Maiti

Novel spectrophotometric method for detection and estimation of butanol in acetone-butanol-ethanol fermenter.

A new, simple, rapid and selective spectrophotometric method has been developed for detection and estimation of butanol in fermentation broth. The red colored compound, produced during reduction of diquat-dibromide-monohydrate with 2-mercaptoethanol in aqueous solution at high pH (>13), becomes purple on phase transfer to butanol and gives distinct absorption at λ520nm. Estimation of butanol in the fermentation broth has been performed by salting out extraction (SOE) using saturated K3PO4 solution at high pH (>13) followed by absorbance measurement using diquat reagent. Compatibility and optimization of diquat reagent concentration for detection and estimation of butanol concentration in the fermentation broth range was verified by central composite design. A standard curve was constructed to estimate butanol in acetone-ethanol-butanol (ABE) mixture under optimized conditions. The spectrophotometric results for butanol estimation, was found to have 87.5% concordance with the data from gas chromatographic analysis.

Low cost semi-continuous bioprocess and online monitoring of hydrogen production from crude glycerol

High process costs arising from expensive media components, hydrogen partial pressure buildup in the head-space of the reactor, sharp decrease in medium pH due to accumulation of organic acids, substrate inhibition, as well as loss of biomass due to short hydraulic retention times are the major bottlenecks of fermentative hydrogen production. Therefore, the purpose of the present investigation was to develop a process to deal with all these problems at a time. The proposed approach demonstrates enhanced hydrogen production by a low cost process involving crude glycerol (CG), the waste from the biodiesel production process, as the only feedstock. This semi-continuous type of fermentation carried out in a 7.5 L bioreactor helped to eliminate substrate inhibition with no compromise in cumulative hydrogen production. By controlling product inhibition and the negative effect of by-product accumulation, as well as by preventing the loss of active biomass, a production of 5.18 L-H2 per L-medium has been achieved. This amount is higher than the 2.02 to 2.68 L-H2 per L-medium previously reported for CG bioconversion. Reduction of feed CG concentration from 120 g L−1 to 60 g L−1 was found to improve the glycerol utilization from 65% to 91%.

Hydrolytic pre-treatment methods for enhanced biobutanol production from agro-industrial wastes.

Brewery industry liquid waste (BLW), brewery spent grain (BSG), apple pomace solid wastes (APS), apple pomace ultrafiltration sludge (APUS) and starch industry wastewater (SIW) have been considered as substrates to produce biobutanol. Efficiency of hydrolysis techniques tested to produce fermentable sugars depended on nature of agro-industrial wastes and process conditions. Acid-catalysed hydrolysis of BLW and BSG gave a total reducing sugar yield of 0.433 g/g and 0.468 g/g respectively. Reducing sugar yield from microwave assisted hydrothermal method was 0.404 g/g from APS and 0.631 g/g from APUS, and, 0.359 g/g from microwave assisted acid-catalysed SIW dry mass. Parameter optimization (time, pH and substrate concentration) for acid-catalysed BLW hydrolysate utilization using central composite model technique produced 307.9 g/kg glucose with generation of inhibitors (5-hydroxymethyl furfural (20 g/kg), furfural (1.6 g/kg), levulinic acid (9.3 g/kg) and total phenolic compound (0.567 g/kg)). 10.62 g/L of acetone-butanol-ethanol was produced by subsequent clostridial fermentation of the substrate.

Butyric Acid: A Platform Chemical for Biofuel and High-Value Biochemicals

Abstract Overpopulation together with an increased demand for fossil fuels led to an overwhelming increase in the demand for liquid fuel and consequently emissions of greenhouse gases. Butyric acid, a short chain fatty acid, is emerging as one of the renewable green C4 platform chemicals that can give an alternative solution to fossil fuels and reduce health and environment-related issues. This chapter presents a comprehensive review of the chemical and biochemical production of butyric acid and its chemical and biochemical utilization to produce mainly green renewable biofuel and other high-value platform chemicals. The main bottlenecks in production, recovery, and the corresponding recent counteractive steps to overcome these challenges are discussed systematically. A special emphasis has been given to the production of butanol, a green alternative solution to fossil fuels using butyric acid as a substrate.

Case Studies on the Industrial Production of Renewable Platform Chemicals

Abstract The depletion and rising cost of fossil fuel reservoirs are giving rise to biorefinery for the transformation of biomass into renewable platform chemicals. Renewable platform chemicals are the best alternative to commercial platform chemicals produced mostly by petrochemical methods using fossil fuels, requiring extreme reaction conditions with concerns over sustainability and environmental issues. Bio-based approaches of producing platform chemicals include CO 2 fixation, with environmental benefits leading to a cost-effective process in comparison to petrochemical production. The industrial conversion depends on a selective synthesis of products at higher yields, with large-scale production, minimum by-products, and efficient separation techniques to obtain high-purity platform chemicals from renewable resources. With the estimated global market of platform chemicals increasing annually, there is a potential for mining platform chemicals in the future.

Nanomaterials in Surface Water and Sediments: Fate and Analytical Challenges

AbstractNanomaterials (NMs) present some interesting properties that may be tailored; for this reason, they are being used in different fields, which leads to their entry into the environment, whether by normal use or intentional delivery. Once in water and sediments, they undergo different transformations that might be difficult to predict. NMs are also difficult to characterize because the methods for this are recently developed. Currently, the most plausible approach is to combine separation and measurement techniques; one of the most versatile integrations is field-flow fractionation with inductively coupled plasma mass spectrometry (ICP–MS) or ICP optical emission spectrometry. In the same way, toxicity assays must be adapted to these emerging contaminants because they behave neither as chemical compounds nor their bulk counterparts, which produces different results. Nevertheless, several adverse effects of NMs exposure on organisms have been reported, including DNA damage, mortality, oxidative stres...

Microwave-assisted one-pot conversion of agro-industrial wastes into levulinic acid: An alternate approach

Brewery liquid waste (BLW), brewery spent grain (BSG), apple pomace solid wastes (APS), apple pomace ultrafiltration sludge (APUS) and starch industry waste (SIW) were evaluated as alternative feedstocks for levulinic acid (LA) production via microwave-assisted acid-catalyzed thermal hydrolysis. LA production of 204, 160, 66, 49 and 12 g/kg was observed for BLW, BSG, APS, APUS, and SIW, respectively, at 140 °C, 40 g/L substrate concentration (SC), 60 min and 2 N HCl (acid concentration). Based on the screening studies, BLW and BSG were selected for optimization studies using response surface methodology. Maximum LA production of 409 and 341 g/kg for BLW and BSG, respectively were obtained at 160 °C, 4.5 M HCl, 85 g/L SC and 27.5 min. Results demonstrated the possibility of using brewery wastes as promising substrates for economical and higher yield production of LA, a renewable platform chemical and versatile precursor for fuels and chemicals.

Acid mediated chemical treatment to remove sugar from waste acid stream from nano-crystalline cellulose manufacturing process.

Nano-crystalline cellulose (NCC) is a nano-scale biomaterial derived from highly abundant natural polymer cellulose. It is industrially produced by concentrated acid hydrolysis of cellulosic materials. However, presences of as high as 5-10% of sugar monomers in spent sulphuric acid during the manufacturing process, makes it unsuitable for such recycling or reuse of sulphuric acid. Currently, the industry has been using membrane and ion exchange technology to remove such sugars, however, such technologies cannot achieve the target of 80-90% removal. In the current investigation, thermal treatment and acid mediated thermal treatment have been evaluated for sugar removal from the spent sulphuric acid. Almost complete removal of sugar has been achieved by this approach. Maximum sugar removal efficiency (99.9%) observed during this study was at 120±1°C for 60min using 0.8 ratio (sample: acid) or at 100±1°C for 40min using 1.5 ratio.

Biobutanol—“A Renewable Green Alternative of Liquid Fuel” from Algae

Increasing global energy demand, concern over global climate changes, and unstable and expensive petroleum resources, have led to the development of renewable energy sources that have driven research toward the utilization of biomass resources for the production of energy and fuels. In this context algae appear to be an emerging source of biomass for biobutanol that has the potential to give an alternative green solution to replace fossil fuel and reduce environmental issues. Biochemical production of butanol, a four carbon aliphatic alcohol, is promising due to its superior fuel properties as compared to ethanol. This chapter presents a comprehensive review on sustainable bioproduction and utilization of butanol as a biofuel and provides a glimpse on different potential biomass and microorganism for biochemical production of butanol. Main bottlenecks in biochemical production and recovery using conventional anaerobic acetone–butanol–ethanol (ABE) fermentation and corresponding recent counteractive steps to overcome these challenges were discussed systematically. A special emphasis has been given on the production of butanol a green alternative solution to fossil fuel using both micro- and macroalgae as potential biomass.