Amit Ganguly

Artificial neural network modelling of xylose yield from water hyacinth by dilute sulphuric acid hydrolysis for ethanol production

Studies on dilute sulphuric acid pretreatment of water hyacinth for xylose yield was carried out with four independent parameters namely temperature, concentration, treatment time and residence time. Response surface methodology (RSM) was implemented to develop an experimental design matrix. Artificial neural network modelling was studied to develop and optimise the process based on the results obtained from the RSM design. The xylose yield under optimised condition obtained experimentally was 164.76 mg/g of dry water hyacinth biomass when hydrolysed with 4.89/ sulphuric acid, at 130°C operating temperature, residence time of 59.67 minutes and treatment time of ten minutes. Enzymatic saccharification was followed using a cocktail of cellulase and xylanase enzyme, which resulted in a total reducing sugar yield of 396.34 mg/g which followed fermentation. A substantial yield of 6.84 g/L of ethanol was obtained using P. stipitis the hydrolysate derived from hydrolysis.

Solid Waste Management in India: A Brief Review

In the twenty-first century, major emphasis should be levied on environmental safety and concern regarding human health. In this relevance, solid waste management need major attention. Awareness in society is profusely obligatory for minimization of solid waste generation. Careful study reveals that municipal solid waste (MSW) provides a major contribution to the total amount of solid waste. But e-wastes are the most frequently growing waste which is also an efficient source of various toxic elements. Globally, upsurge in the demand of nuclear energy enhances the generation of radioactive solid waste (RSW) that may be responsible for harmful effect of radiation. On the other hand, hospital solid wastes (HSWs) have great impact on environment and public health as it is the carrier of infectious diseases and other toxic elements. Biodegradable organics are the major content of agriculture solid waste (ASW) along with some pesticides and heavy metals. The total amount of solid waste (SW) is enhancing day by day, and as a consequence proper solid waste management (SWM) methods are necessary which could minimize the total amount of SW as well as its hazardous effect on environment. This review is focused on generation of different SWs and corresponding techniques of SWM starting from conventional tools to modern technique like refuse-derived fuel (RDF), pyrolysis, incineration together with their advantages and limitations.

Production of Ethanol from Waste Potato Using Locally Available Biocatalyst

Bioethanol is a renewable energy source produced from the resources which can be easily replenished. The bioethanol production through fermentation may provide an economically competitive source of energy by its incorporation into gasoline. Production of bioethanol from waste food crops like potatoes could be the better substrate, and the waste produced is also biodegradable. Lack of storage facilities and postharvest losses make potato a promising crop which can be used for production of ethanol. Moreover, the conversion of potato starch into glucose by bakhar is more cost-effective, and fermentation with baker’s yeast Saccharomyces cerevisiae yields maximum amount of ethanol. This process of production of ethanol from waste potato would be promising and economically effective for the production of biofuel, called bioethanol.

INVESTIGATIONS ON MICROBIAL FERMENTATION OF HEMICELLULOSE HYDROLYSATE FOR XYLITOL PRODUCTION

A crude trial on microbial fermentation of dilute acid treated hemicellulose hydrolysate of water hyacinth (Eichhornia crassipes) biomass was performed in batch culture in a BOD rotary shaker using four different species as Candida shehatae, Pichia stipitis, Candida tropicalis and Debaromyces hansenii under various parameters to check the optimal xylitol production. The hydrolysate was concentrated using a vacuum evaporator at 70C and detoxified using activated charcoal (5 %) which efficiently removed 83 % of inhibitory phenolic biproducts. Effect of nutrients concentration, pH (4.5, 5.5, 6.5), temperature (20, 30, 40C) and agitation speed (150, 200, 250 rpm) on growth of different yeast and xylitol production was studied and compared. The optimal xylitol yield was found to be 0.65 g xylitol/g of xylose from Candida tropicalis at 30C, pH 5.5 with an agitation of 200 rpm, 2.5 g/L ammonium sulphate as a nutrient and 0.615 xylitol/g of xylose from Pichia stipitis respectively after 72 h of incubation. Keyword: Microbial fermentation, water hyacinth biomass, xylitol production, yeast, detoxification.