High level xylitol production by Pichia fermentans using non-detoxified xylose-rich sugarcane bagasse and olive pits hydrolysates

Hemicellulosic 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

Synthesis and application of TiO2-supported phosphotungstic acid for ethyl levulinate production

The present study investigates synthesis, characterization, and application of TiO2 supported Keggin phosphotungstic acid in biorenewable transformations. In particular, 10 wt%, 20 wt%, 30 wt% and 40 wt% Keggin phosphotungstic acid was loaded over TiO2 support via wet impregnation method to prepare EPTN-1, EPTN-2, EPTN-3, and EPTN-4 catalysts, respectively. After this, synthesized catalysts were tested in a microwave reactor to measure reactivity trend in order HPW > EPTN-4 > EPTN-3 > EPTN-2 > EPTN-1. A maximum 95% levulinic acid (LA) conversion was measured in the presence of 72 mg EPTN-4 catalyst, two mmol LA in 1:42 LA: EtOH (ethanol) molar ratio at 393 K in 120 min at a stirring speed of 300 rpm. No significant loss in heterogenized EPTN-4 catalyst was measured after five application cycles. A detailed characterization of synthesized catalyst showed that the Keggin structure remained intact after heterogenization

Valorization of Microcrystalline Cellulose Using Heterogeneous Protonated Zeolite Catalyst: An Experimental and Kinetics Approach

This study aimed to valorize microcrystalline cellulose (MCC) using protonated zeolite catalysts such as (H-ZSM-5) and Cr/H-ZSM-5 (5%) in ionic liquid. The catalytic effect in synergy with 1-butyl-3-methylimidazolium Chloride ([BMIM] Cl) ionic liquid was studied in detail. The total reducing sugar (TRS) was determined using the 3, 5-dinitrisalcylic acid (DNS) array method. The catalysts were characterized using techniques such as Fourier transform infrared (FT-IR), X-ray diffraction analysis (XRD), temperature-programmed desorption of ammonia (NH3-TPD), and BET-surface area analyzer. H-ZSM-5 effectively depolymerized cellulose with a maximum yield of 70% total reducing sugar (34% glucose, 8% fructose, and 4.5% 5-HMF). Cr/H-ZSM-5 catalyst dehydrated fructose to 5-HMF with a yield of 53%. The use of ionic liquid significantly reduced the activation energy of formation and decomposition. The activation energy determined in cellulose hydrolysis was 85.83 KJ mol−1 for a reaction time of 180 min while the decomposition energy was found to be 42.5 kJ mol−1

Thermal pyrolysis of polyolefins in a two-step process: Role of secondary reactions

396-403Thermal cracking of HDPE has been investigated in a two-step process. The primary pyrolysis takes place in the first reactor while the second reactor allows vapor phase secondary reactions to take place. The effect of residence time (RT) and temperature in the secondary reactor on the liquid product (LP) profile has been elucidated. The change in RT does not significantly alter the B.P. distribution of the LP; however, an increase in the RT leads to a reduction in the total olefinic content but with a simultaneous increase in the percentage of lower olefins (C6-C8). An increase in temperature from 350 to 450ºC results in the shifting of carbon number distribution to lower values along with an increase in total olefinic content. Thus the second reactor conditions, in a two-step process, plays a major in controlling the LP profile and a suitable choice of the same can help in obtaining desirable products

Valorization of Microcrystalline Cellulose Using Heterogeneous Protonated Zeolite Catalyst: An Experimental and Kinetics Approach

This study aimed to valorize microcrystalline cellulose (MCC) using protonated zeolite catalysts such as (H-ZSM-5) and Cr/H-ZSM-5 (5%) in ionic liquid. The catalytic effect in synergy with 1-butyl-3-methylimidazolium Chloride ([BMIM] Cl) ionic liquid was studied in detail. The total reducing sugar (TRS) was determined using the 3, 5-dinitrisalcylic acid (DNS) array method. The catalysts were characterized using techniques such as Fourier transform infrared (FT-IR), X-ray diffraction analysis (XRD), temperature-programmed desorption of ammonia (NH3-TPD), and BET-surface area analyzer. H-ZSM-5 effectively depolymerized cellulose with a maximum yield of 70% total reducing sugar (34% glucose, 8% fructose, and 4.5% 5-HMF). Cr/H-ZSM-5 catalyst dehydrated fructose to 5-HMF with a yield of 53%. The use of ionic liquid significantly reduced the activation energy of formation and decomposition. The activation energy determined in cellulose hydrolysis was 85.83 KJ mol−1 for a reaction time of 180 min while the decomposition energy was found to be 42.5 kJ mol−1

Photocatalytic Conversion of Carbon Dioxide and Nitrogen Dioxide: Current Developments, Challenges, and Perspectives

The pursuit of carbon-neutral processes has gained traction due to a growing awareness of global warming. This drives the expectation of solar fuel growth through renewable sources. Photocatalytic reactions offer a way to harness solar energy for dense fuels, storing and transporting it via chemical bonds. These efforts directly address society’s rising energy needs. Notably, photocatalytic CO2 reduction and N2 fixation stand out for renewable fuel production and reducing reliance on fossils. Investigating these reactions is crucial. This review covers concepts, strategies, thermodynamics, and nanostructured photocatalysts in CO2 and N2 conversions. It provides insights for researchers, scientists, and newcomers, offering a broader view of solar-to-fuel experiments and intricate reaction mechanisms

A State-of-the-Art Review on the Technological Advancements for the Sustainable Management of Plastic Waste in Consort with the Generation of Energy and Value-Added Chemicals

Plastic waste poses a serious threat to the environment and it has been increasing at an alarming rate. In 2022, global plastic waste generation was reported to be around 380 million tonnes as compared to 353 million tonnes in 2019. Production of liquid fuel from plastic waste is regarded as a viable method for disposing of the plastic and utilizing its energy. Currently, a wide range of technologies have been explored for turning plastic waste into fuel, including the conventional pyrolysis, incineration, gasification and advanced oxidation. However, a systematic summary and comparative analysis of various technologies has still not reported. Traditional non-biodegradable plastic waste (NPW) treatment methods include landfilling and incineration, but these methods encounter bottlenecks and are unable to adequately address NPW issues. This review attempts to present a thorough summary of treatment methods for plastic waste (both conventional and novel treatment technologies that have recently been reported), examine their mechanism and their current state of development. Furthermore, the superiority and drawbacks of each technology are analysed and the prospects of technology application are proposed. By tackling the problems of white pollution and energy scarcity, this review intends to inspire the use of solid waste as a source of energy

Eco-Friendly Preservation of Bamboo Species: Traditional to Modern Techniques

The continuous depletion of forests calls for the astute usage of existing resources. Fungi and termites cause serious damage to biomass under storage and service conditions. Various protective treatments with high amounts of toxic chemicals are used by the wood and bamboo industry. Efforts are being made the world over to develop environmentally friendly preservatives for wood and bamboo species. Recent research highlights the potential and effectiveness of traditional practices and procedures, mainly water leaching technique and smoke treatment. Under laboratory conditions, the service life of treated blocks were found to be at a par with commercial chemical preservative treated blocks. Various plant extracts and oil-based formulations, such as organic acids, essential oils, and eco-friendly chemical-based preservatives, are in the stage of development. The bio-efficacy of such preservatives is measured in terms of the improvement in resistance to fungi and termites. However, much work still needs to be done to completely determine the efficacy of many of these newly developed preservatives and techniques. The present paper discusses an overview of the developments in the field of environment-friendly biomass preservatives