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Current Funded Projects and Independent Studie
s

Ratna R. Sharma

Department of Biological And Agricultural Engineering
North Carolina State University
Campus Box 7625, Raleigh, NC 27695-7625
Phone: (919) 515-6746
Email: ratna_sharma@ncsu.edu


Studies are currently underway for determination of optimal pretreatment and hydrolysis conditions to generate fermentable sugars from Miscanthus varieties.
Effects of harvest time, preparation, and plant part are being investigated to determine ethanol production potential of various switchgrass varieties grown in North Carolina.
Switchgrass pretreatment
  • Conversion of hays and straws to bioethanol (in collaboration with Montana State University)
The potential of a variety of hay and straw based feedstocks such as wheat, barley, pearl millet and triticale for bioethanol production is being explored.
 

Potential of fermenting sugarbeet juice to poly-hydroxybutyrate (PHB), a biodegradable plastic, is being investigated. 
Potential of fermenting sweetpotatoes to high value polymers such as glutamic acid, lactic acid and poly-hydroxybutyrate (PHB) is being investigated. It is expected that results of these studies can be applied to waste potato streams and other sugar platforms.

Bioconversion of cotton stalks to fuel ethanol can benefit both the environment and economics of North Carolina.
Microbial pretreatment, utilizing Phanerochaete chrysosporium, has advantages such as energy-saving,
environmental friendliness, simple processes and equipment, and low cost. In this study treatment parameters
will be optimized and growth kinetics modeled for scale up. Lastly, microbial pretreatment will be compared with
other pretreatment methods.




Subcritical water can be used to pretreat lignocellulosic biomass to enhance ethanol yields. It is an environment friendly approach since it does not leave behind chemical residues and eliminates the need for sugar separation from treatment solution. This study is investigating the effect of time, temperature and particle size on pretreatment effeciency.

The conversion of lignocellulosic biomass to ethanol involves pretreatment to remove lignin and hemicellulose, reduce cellulose crystallinity, and increase porosity of the material; hydrolysis, acid or enzymatic, to convert cellulose to reducing sugars such as glucose and fermentation of the reducing sugars to ethanol by yeast or bacteria. The objective of this study is to investigate the effect of sulfuric acid, sodium hydroxide, and ozone pretreatments on the delignification and enzymatic digestibility of cotton stalks which are abundant in North Carolina.


This project seeks to validate the hypothesis that inert porous substrates coated with multiple nanolayers of polyelectrolytes
can be used as selective membranes for the pervaporation of bioethanol produced from cotton stalk. Current processes used
for separation of ethanol from fermentation medium involve energy intensive methods such as distillation, evaporation, and
ultrafiltration and are also limited in their specificity for product and by-product removal.  Some of these separation methods
operate at elevated temperatures that kill microorganisms limiting their reuse in the fermentation processes.  Membrane based
separation systems are an attractive alternative to these traditional techniques as they are less costly and can operate at lower
temperatures.


Capsaicin, an alkaloid or capsaicinoid, is the principal pungent and irritating constituent of hot peppers that are widely used as food additives and possess antimicrobial properties. This project aims at examining the processing parameters for solvent extraction and quanitfication of capsaicinoids from whole habanero peppers (Capsicum chinense) and their various parts.The overall goal of the project is to redefine chili peppers as a value added crop for North Carolina farmers, by developing processing methods for effective capsaicin recovery. The results of the study will be used to conduct subsequent research on SCFE as an environment friendly, product specific alternative to solvent extraction of capsaicin and to investigate its use in food processing.

The project aims at extracting high value compounds like anthocyanin from purple sweet potatoes and secondary metabolites from tobacco using the environmentally benign supercritical CO2 technology.

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