Biotechnical Engineering

Research Overview

Biotechnology offers new ways of production using biological materials, organisms and systems. Leading research in this area enables the synthesis of pharmaceuticals, biodegradable polymers, renewable fuels, and other bio-based products from diverse feedstocks.

Faculty are developing new crops for improved disease and pest resistance and adaptation to changing climate and conditions. We are also improving waste treatment and conversion, reducing environmental impact and enhancing overall sustainability. Examples include the following and more:

  • New microbial strains with modified biochemical pathways for biofuels and bioproducts
  • Enzyme systems to improve biomass conversion for biofuels, biochemcials, and other bioproducts
  • Nanomaterials and soft-tissue engineering for new fibers and textiles, biocarbons and energy storage technologies
  • Algal cultivation systems and improved understanding of algal metabolomics for advanced biofuels
  • Novel anaerobic systems for waste management and biogas production
  • Thermochemical conversion processes for bioenergy and biofuels

Click here to see more examples and potential career paths in Biotechnical Engineering.

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Recent Research Results

Cross-Linked Alginate Microcapsules (CLAMs)

CLAM Research Biological and Agricultural Engineering UC Davis
Powder size distributions for spray-dried CLAMs.

"In situ cross-linking of alginate during spray-drying to microencapsulate lipids in powder": Microencapsulation of emulsified lipophilic bioactive compounds in dry, cross-linked alginate microcapsules (CLAMs) is a promising strategy to facilitate their incorporation into food systems, prolong shelf life, and target delivery within the gastrointestinal tract. However, current technology to produce CLAMs requires multiple time- and energy-intensive unit operations...Coupled with the scalability of this novel CLAM production method, the successful encapsulation of the model lipid suggests that spray-dried CLAMs may be of commercial use for incorporating lipophilic compounds into foods.

CLAM BAE UC Davis
SEM images of CLAMs. 25% oil CLAMs appear approximately spherical with dimpled surfaces (A). Cross-section of 25% oil CLAMs shows oil droplet distribution within these CLAMs (B). 0% oil CLAMs have a collapsed appearance with smooth surfaces (C). Scale bars represent 5 mm.

Strobel, S.A., Scher, H.B., Nitin, N. and Jeoh, T., 2016. In situ cross-linking of alginate during spray-drying to microencapsulate lipids in powder. Food Hydrocolloids, 58, pp.141-149.

Cellulase-Cellulose Interactions

Cellulose microfibrillar structure changes biolgocial and agricultural engineering uc daivs
ABA washed BC fibrils immobilized on glass. These images correspond to the substrate-only control and zero time point in the hydrolysis experiments. (A) 10 m × 10 m field of view (FOV) (dimensions of the image shown). Left: AFM height image, right: cross-section height profile corresponding to the white line in the height image; (B and C) 1 m × 1 m FOV. Left: height data, right: phase data.

"Assessing cellulose microfibrillar structure changes due to cellulase action": There is a need to understand how cellulose structural properties impact productive cellulase–cellulose interactions toward solving the mechanisms of the heterogeneous reaction. We coupled biochemical studies of cellulose hydrolysis by a purified Trichoderma reesei Cel7A (TrCel7A) cellobiohydrolase with atomic force microscopy (AFM) to study the impact of the cellulolytic activity on the fibrillar structure of cellulose...We observed extensive fibrillation of BC fibrils to ∼3 nm microfibrils during the course of hydrolysis by TrCel7A, leaving thinned un-fibrillated recalcitrant fibrils at >80% hydrolysis extents. Additionally, this remaining fraction appeared to be segmented along the fibril length."

Jeoh, T., Santa-Maria, M.C. and O’Dell, P.J., 2013. Assessing cellulose microfibrillar structure changes due to cellulase action. Carbohydrate polymers, 97(2), pp.581-586.

 

Cellobionic Acid as Viable Carbon Source for Biofuel Producation

Isobutanol producation from cellobionic acit en Escherichia coli biological and Agricultural Engineering UC Davis
Isobutanol titers
from strain AL17(pAL603) after 24 hours of production in M9 Production Media. 20gL Glu; 20 g/L glucose, 16gL Glu; 16 g/L glucose, 10gL Glu; 10 g/L glucose, GA; 20 g/L gluconate, Glu:GA; 10 g/L glucose and 10 g/L gluconate, CBA com; 10.4 g/L commercial CBA, CBA Syn; 16.9 g/L biologically synthesized CBA. B. Growth of isobutanol host strain AL17(pAL603) during production period. Where n = 3 biologicalreplicates, and error bars represent standard deviation.

"Isobutanol produciton from cellobionic acid in Escherichia coli": Liquid fuels needed for the global transportation industry can be produced from sugars derived from plant-based lignocellulosics. Lignocellulosics contain a range of sugars, only some of which (such as cellulose) have been shown to be utilizable by microorganisms capable of producing biofuels. Cellobionic acid makes up a small but significant portion of lignocellulosic degradation products, and had not previously been investigated as an utilizable substrate...This study describes the discovery that Escherichia coli are naturally able to utilize cellobionic acid as a sole carbon source with efficiency comparable to that of glucose and the construction of an a E. coli strain able to produce the drop-in biofuel candidate isobutanol from cellobionic acid...These results demonstrate that cellobionic acid is a viable carbon source for biofuel production.

Desai, S.H., Rabinovitch-Deere, C.A., Fan, Z. and Atsumi, S., 2015. Isobutanol production from cellobionic acid in Escherichia coli. Microbial cell factories, 14(1), p.1.

Systems Analysis and Optimization

"Economic sustainability modeling provides decision support for assessing hybrid poplar-based biofuel development in California":

UC Davis Biological and Agricultural Engineering Biotechnical Engineering Assessment and Optimization
Integrated modeling framework used to assess the feasibility of poplar-based biofuel in Northern California. This framework consists of models and commercial software to assess various sustainability aspects related to poplar-based biofuel industry development. The arrows reflect the flows of data from model to model.

Biofuels are expected to play a major role in meeting California's long-term energy needs, but many factors influence the commercial viability of the various feedstock and production technology options. We developed a spatially explicit analytic framework that integrates models of plant growth, crop adoption, feedstock location, transportation logistics, economic impact, biorefinery costs and biorefinery energy use and emissions...However, there are major obstacles to such large-scale production, including, on nonarable lands, low poplar yields and broad spatial distribution and, on croplands, competition with existing crops. We estimated the production cost of jet fuel to be $4.40 to $5.40 per gallon for poplar biomass grown on nonarable lands and $3.60 to $4.50 per gallon for biomass grown on irrigated cropland; the current market price is $2.12 per gallon.

UC Davis Assessment and Optimization Biological and Agricultural Engineering Biotechincal Engineering
Possible sites for independent 100-million-gallon per year (MGY) biorefineries in Northern California and optimum jet fuel price for each site based on biomass supply from both suitable croplands and nonarable lands (nonirrigated pasture and grasslands).

Bandaru, V., Parker, N., Hart, Q., Jenner, M., Yeo, B., Crawford, J., Li, Y., Tittmann, P., Rogers, L., Kaffka, S. and Jenkins, B., 2015. Economic sustainability modeling provides decision support for assessing hybrid poplar-based biofuel development in California. California Agriculture, 69(3), pp.171-176.