Jianfeng (Jay) Xu - Associate Professor

Xu pic
Phone: 870-680-4812 (Office); 870-680-4394 (Lab)
Address: Arkansas Biosciences Institute at Arkansas State University | PO Box 639 | State University, AR 72467
Email: jxu@astate.edu

Affiliations:

ASU,  Arkansas Biosciences Institute

 Cluster Identification:
- Plant Productivity ‘Set-Points’ Cluster

Research Areas/Expertise:
- Algae for biofuels & bioproduction
- Bioengineering
- Biofuels & biobased products
- Feedstock processing
- Phytochemicals & human health
- Plant cell walls
- Plant-made industrial/ pharmaceutical proteins
- Plant tissue culture
- Protein processing & trafficking 

Research Summary | Selected Publications | Lab Members | Key Collaborators | Research Projects | Links

Research Summary:

Research in the Xu’s group is currently focused in two areas: 1) plant cell as a bioproduction platform for recombinant proteins, and 2) bioprocess engineering to convert cellulosic biomass to biofuels. In plant cell bioproduction system, a proprietary “Hydroxyproline-Glycosylation (Hyp-Glyco)” technology has been used to significantly enhance the production of secreted proteins and improve the stability and solubility of the target protein. We are now extending the Hyp-Glyco technology to green algae, hairy root and transient plant expression system. We are also scaling up the plant cell culture in bioreactor and establish continuous perfusion culture to increase protein productivity. For the second research area, we are working on cellulosic ethanol production from dedicated energy crops, such as gamagrass, switchgrass and miscanthus.  We develop entire biomass-to-ethanol conversion process including biomass pretreatment, enzymatic hydrolysis and fermentation (partially with self-flocculating yeast). Most recently, we try to reconstruct the plant cell wall for better digestibility by using the Hyp-Glyco technology.

Selected Publications:

Zhang N, Green S, Ge X, Savary BJ, Xu J. 2014. Ethanol fermentation of energy beets by self-flocculating and non-flocculating yeasts. Bioresour. Technol., 155:189-197.

Dolan MC, Wu D, Cramer CL, Xu J. 2014. Hydroxyproline-O-glycosylated peptide tags enhance recombinant protein yields in tobacco transient expression. Process Biochem., 29(3):490-495.

Xu J, Dolan MC, Medrano G, Cramer CL, Weathers PJ. 2012. Green factory: plants as bioproduction platforms for recombinant proteins. Biotechnol. Adv., 30(5):1171-1184.

Ge X, Zhang N, Phillips, Xu J. 2012. Growing Lemna minor in agricultural wastewater and converting the duckweed biomass to ethanol. Bioresour. Technol., 124:485-488.

Ge X, Luo D, Xu J. 2011. Cell free protein expression under macromolecular crowding environments. PLoS One, 6(12): e28707.

Xu J, Ge X, Dolan MC. 2011. Towards high-yield production of therapeutic proteins with plant cell suspension culture. Biotechnol. Adv., 29(3): 278-299.

Tan L, Varnai P, Lamport DT, Yuan C, Xu J, Qiu F, Cottrell C, Kieliszewski M. 2010. O-Hyp arabinogalactans of arabinogalactan proteins are beta-(1-6) linked repeats of beta-(1-3) trigalactosyl subunits with short bifurcated sidechains. J. Biol. Chem., 285(32): 24575-24583.

Lab Members:

 

Jianfeng (Jay) Xu, PhD, Arkansas Biosciences Institute
Assistant Professor, College of Agriculture and Technology
jxu@astate.edu; 870-680-4394

   

NingNing Zhang
PhD student (MBS program)
P3 fellowship
ningning.zhang@smail.astate.edu; 870-680-4394

Hong Fang
Masters student (Agriculture)
zhiqiang.zhao@smail.astate.edu; 870-680-4394

Christopher Elms
Undergraduate student (Biology)
P3 Internship (2013); SURF Recipient (2014); ASSET Summer Internship (2014)
christop.elms@smail.astate.edu; (870) 307-4476

Zachary (Carter) Lee
Undergraduate student (Biology)
P3 Internship (2014/2015)
zachary.lee1@smail.astate.edu; (501)951-0879

 

Key Collaborators

Dr. Carole Cramer, biotechnology | Arkansas State University, Jonesboro
Dr. Maureen Dolan, biotechnology | Arkansas State University, Jonesboro
Dr. Gregory Phillips, agriculture | Arkansas State University, Jonesboro
Dr. Steven Green, soil and water conservation | Arkansas State University, Jonesboro
Dr. Marcia Kieliszewski, biochemistry| Ohio University, Athens, OH
Dr. David N. Radin, entrepreneur, plant-based bioproduction | BioStrategies LC, Jonesboro, AR
Dr. Brett Savary, carbohydrate chemistry | Arkansas State University, Jonesboro
Dr. Pamela Weathers, biochemical engineering | Worcester Polytechnic Institute, Worcester, MA

Research Projects

A high-yield plant cell production platform for secreted proteins.  Plant cell culture is potentially a safe and cost-effective biosynthetic platform for valuable proteins. However, low protein production is a bottleneck towards commercializing this technology. This projectl is aimed at overcoming this bottleneck by leveraging a new strategy, termed Hyp-Glyco technology, which will deliver higher secreted protein yields and potentially enhance clinical properties of therapeutic proteins. The Hyp-Glyco technology involves expressing recombinant proteins as fusions with novel glycomodule tags comprised of hydroxyproline (Hyp)-rich repetitive peptide (HypRP) backbones. Specific aims of this project include: 1) Develop optimal/minimum HypRP design that facilitates high-yield protein secretion; 2) Develop efficient HypRP tag cleavage approaches to recover native proteins; 3) Express therapeutic proteins to test the practical and broad applications of Hyp-Glyco technology; 4) Establish optimal bioreactor operating strategies to further enhance the production of secreted proteins.

 

 

Designer biopolymer for reconstructing plant cell wall.  Cellulosic ethanol production from plant biomass holds great potential as an alternative biofuel source. However, due to the complex structural nature of plant cell wall polysaccharides restricting penetration of chemicals and enzymes to their substrates, cellulosic biomass is much more recalcitrant than starch to break down into fermentable sugars for biofuel production. Most current efforts to genetically engineer improved feedstock more amenable for degradation have been focused on the modification of the cell wall components and the lignin biosynthesis pathways. These modifications often lead to reduction of plant fitness.  We develop an alternative approach that avoids manipulating autologous plant genes to reconstruct plant cell wall. Our approach works by engineering into plants novel designer biopolymers (with or without fusion to a cell wall-modifying enzyme) that will be secreted in the course of cell wall development and to intercalate between cellulose fibers or serve as soluble ‘‘hemicellulose-like’’polymers, creating soluble ‘‘pockets’’. Plants with such characteristics will behave normally during plant growth, but permit rapid solvent and enzyme penetration during biomass processing. We will first engineer such designer biopolymers into model plants Arabidopsis thaliana and tobacco.  Knowledge gained from the research with Arabidopsis will be translated to dedicated energy crops such as switchgrass and miscanthus.

Microalgae as new bioproduction platform for recombinant proteins. Green microalgae combine the merits of both eukaryotic and prokaryotic organism culture system and offer high protein content, which make them ideal hosts for the large-scale sustainable production of recombinant proteins. The scope of this project is to establish microalgae Chlamydomonas reinhardtii as an efficient bioproduction platform. We will use enhanced green fluorescence protein (EGFP) as model protein to investigate the nuclear and plastid transformation, gene expression, protein secretion and process development. We will then express other proteins with potential pharmaceutical application such as vaccine in the C. reinhardtii. In addition, since the cell wall of green microalgae are  rich in hydroxyproline (Hyp)-rich glycoproteins (HRGPs), we will also characterize the Hyp-O-glycosylation pattern/code of the microalgae by expressing synthetic gene constructs encoding HRGPs such as tandem repeats of “Ser-Pro” and “Ser-Pro-Pro Pro-Pro” motif in C. reinhardtii.

Links