15 research outputs found
Nanofibers Produced from Agro-Industrial Plant Waste Using Entirely Enzymatic Pretreatments
Cellulose
fibers can be freed from the cell-wall skeleton via high-shear
homogenization, to produce cellulose nanofibers (CNF) that can be
used, for example, as the reinforcing phase in composite materials.
Nanofiber production from agro-industrial byproducts normally involves
harsh chemical-pretreatments and high temperatures to remove noncellulosic
polysaccharides (20–70% of dry weight). However, this is expensive
for large-scale processing and environmentally damaging. An enzyme-only
pretreatment to obtain CNF from agro-industrial byproducts (potato
and sugar beet) was developed with targeted commercial enzyme mixtures.
It is hypothesized that cellulose can be isolated from the biomass,
using enzymes only, due to the low lignin content, facilitating greater
liberation of CNF via high-shear homogenization. Comprehensive Microarray
Polymer Profiling (CoMPP) measured remaining extractable polysaccharides,
showing that the enzyme-pretreatment was more successful at removing
noncellulosic polysaccharides than alkaline- or acid-hydrolysis alone.
While effective alone, the effect of the enzyme-pretreatment was bolstered
via combination with a mild high-pH pretreatment. Dynamic rheology
was used to estimate the proportion of CNF in resultant suspensions.
Enzyme-pretreated suspensions showed 4-fold and 10-fold increases
in the storage modulus for potato and sugar beet, respectively, compared
to untreated samples. A greener yet facile method for producing CNF
from vegetable waste is presented here
A Germin-Like Protein Gene (CchGLP) of Capsicum chinense Jacq. Is Induced during Incompatible Interactions and Displays Mn-Superoxide Dismutase Activity
A germin-like gene (CchGLP) cloned from geminivirus-resistant pepper (Capsicum chinense Jacq. Line BG-3821) was characterized and the enzymatic activity of the expressed protein analyzed. The predicted protein consists of 203 amino acids, similar to other germin-like proteins. A highly conserved cupin domain and typical germin boxes, one of them containing three histidines and one glutamate, are also present in CchGLP. A signal peptide was predicted in the first 18 N-terminal amino acids, as well as one putative N-glycosylation site from residues 44–47. CchGLP was expressed in E. coli and the recombinant protein displayed manganese superoxide dismutase (Mn-SOD) activity. Molecular analysis showed that CchGLP is present in one copy in the C. chinense Jacq. genome and was induced in plants by ethylene (Et) and salicylic acid (SA) but not jasmonic acid (JA) applications in the absence of pathogens. Meanwhile, incompatible interactions with either Pepper golden mosaic virus (PepGMV) or Pepper huasteco yellow vein virus (PHYVV) caused local and systemic CchGLP induction in these geminivirus-resistant plants, but not in a susceptible accession. Compatible interactions with PHYVV, PepGMV and oomycete Phytophthora capsici did not induce CchGLP expression. Thus, these results indicate that CchGLP encodes a Mn-SOD, which is induced in the C. chinense geminivirus-resistant line BG-3821, likely using SA and Et signaling pathways during incompatible interactions with geminiviruses PepGMV and PHYVV