High-yield kraft pulping of Eucalyptus grandis Hill ex Maiden biotreated by Ceriporiopsis subvermispora under two different culture conditions

Holzforschung ◽  
2009 ◽  
Vol 63 (4) ◽  
Author(s):  
Marcos Paulo Vicentim ◽  
Robson de Almeida Faria ◽  
André Ferraz

AbstractIn the present study, it was evaluated how two different culture conditions for the biotreatment ofEucalyptus grandisbyCeriporiopsis subvermisporaaffect a subsequent high-yield kraft pulping process. Under the varied culture conditions investigated, different extracellular enzyme activities were observed. Manganese-peroxidase (MnP) secretion was 3.7 times higher in cultures supplemented with glucose plus corn-steep liquor (glucose/CSL) as compared to non-supplemented (NS) cultures. The biotreated samples underwent diverse levels of wood component degradation as losses of weight and lignin were increased in glucose/CSL cultures. Mass balances for lignin removal during kraft pulping showed that delignification was facilitated when both biotreated wood samples were cooked. Delignification efficiency did not correlate positively with MnP levels in the cultures. On the other hand, biopulps from NS and glucose/CSL cultures saved 27% and 38% beating time to achieve 28° Schopper-Riegler freeness during refining, respectively. Biopulps disposed of decreased tensile and tear resistances, thus easier refining of the biokraft pulps seems to be a consequence of less resistant fiber walls. Improved beatability of biopulps was tentatively related to short fibers and fines formation during refining. We suggest that to some extent polysaccharide depolymerization occurred during the biotreatment, which also resulted in diminished pulp yields in the case of glucose/CSL cultures.

Holzforschung ◽  
2008 ◽  
Vol 62 (4) ◽  
Author(s):  
Marcos Paulo Vicentim ◽  
André Ferraz

Abstract The effect of different culture conditions have been evaluated concerning the extracellular enzyme activities of the white-rot fungus Ceriporiopsis subvermispora growing on Eucalyptus grandis wood. The consequence of the varied fungal pretreatment on a subsequent chemithermomechanical pulping (CTMP) was addressed. In all cultures, manganese peroxidase (MnP) and xylanase were the predominant extracellular enzymes. The biopulping efficiency was evaluated based on the amount of fiber bundles obtained after the first fiberizing step and the fibrillation levels of refined pulps. It was found that the MnP levels in the cultures correlated positively with the biopulping benefits. On the other hand, xylanase and total oxalate levels did not vary significantly. Accordingly, it was not possible to determine whether MnP accomplishes the effect alone or depends on synergic action of other extracellular agents. Pulp strength and fiber size distribution were also evaluated. The average fiber length of CTMP pulps prepared from untreated wood chips was 623 μm. Analogous values were observed for most of the biopulps; however, significant amounts of shorter fibers were found in the biopulp prepared from wood chips biotreated in cultures supplemented with glucose plus corn-steep liquor. Despite evidence of reduced average fiber length, biopulps prepared from these wood chips presented the highest improvement in tensile indexes (+28% at 23° Schopper-Riegler).


2021 ◽  
Vol 2 (2) ◽  
pp. 234-244
Author(s):  
Thomas P. West

This review examines the production of the microbial polysaccharide gellan, synthesized by Sphingomonas elodea, on dairy and plant-based processing coproducts. Gellan is a water-soluble gum that structurally exists as a tetrasaccharide comprised of 20% glucuronic acid, 60% glucose and 20% rhamnose, for which various food, non-food and biomedical applications have been reported. A number of carbon and nitrogen sources have been tested to determine whether they can support bacterial gellan production, with several studies attempting to optimize gellan production by varying the culture conditions. The genetics of the biosynthesis of gellan has been explored in a number of investigations and specific genes have been identified that encode the enzymes responsible for the synthesis of this polysaccharide. Genetic mutants exhibiting overproduction of gellan have also been identified and characterized. Several dairy and plant-based processing coproducts have been screened to learn whether they can support the production of gellan in an attempt to lower the cost of synthesizing the microbial polysaccharide. Of the processing coproducts explored, soluble starch as a carbon source supported the highest gellan production by S. elodea grown at 30 °C. The corn processing coproducts corn steep liquor or condensed distillers solubles appear to be effective nitrogen sources for gellan production. It was concluded that further research on producing gellan using a combination of processing coproducts could be an effective solution in lowering its overall production costs.


1993 ◽  
Vol 39 (10) ◽  
pp. 978-981 ◽  
Author(s):  
A. B. Salleh ◽  
R. Musani ◽  
M. Basri ◽  
K. Ampon ◽  
W. M. Z. Yunus ◽  
...  

A thermophilic Rhizopus oryzae was isolated, and parameters affecting its production of extra- and intra-cellular lipases were investigated. All carbon sources tested with the exception of sucrose generally inhibited the production of extracellular lipase, but enhanced the production of intracellular lipase. Peptone was the best substrate for extracellular enzyme production, but for intracellular lipase production other substrates such as tryptone, tryptic soy digest, polypeptone, and corn steep liquor gave comparable results. Among lipid substrates, glycerol was the only stimulator of extracellular enzyme production, whereas olive oil, triolein, and oleic acid had very positive effects on intracellular enzyme production. Shaking enhanced the production of both types of enzymes; the temperature optima were 45 and 37 °C for extra- and intra-cellular lipases, respectively. A pH of 5.0 was optimal for production of both enzymes.Key words: lipases, Rhizopus oryzae, production.


Holzforschung ◽  
2008 ◽  
Vol 62 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Fernando Masarin ◽  
André Ferraz

Abstract In biopulping, efficient wood colonization by a selected white-rot fungus depends on previous wood chip decontamination to avoid the growth of primary molds. Although simple to perform in the laboratory, in large-scale biopulping trials, complete wood decontamination is difficult to achieve. Furthermore, the use of fungal growth promoters such as corn steep liquor enhances the risk of culture contamination. This paper evaluates the ability of the biopulping fungus Ceriporiopsis subvermispora to compete with indigenous fungi in cultures of fresh or poorly decontaminated Eucalyptus grandis wood chips. While cultures containing autoclaved wood chips were completely free of contaminants, primary molds grew rapidly when non-autoclaved wood chips were used, resulting in heavily contaminated cultures, regardless of the C. subvermispora inoculum/wood ratio evaluated (5, 50 and 3000 mg mycelium kg−1 wood). Studies on benomyl-amended medium suggested that the fungi involved competed by consumption of the easily available nutrient sources, with C. subvermispora less successful than the contaminant fungi. The use of acid-washed wood chips decreased the level of such contaminant fungi, but production of manganese peroxidase and xylanases was also decreased under these conditions. Nevertheless, chemithermomechanical pulping of acid-washed samples biotreated under non-aseptic conditions gave similar fibrillation improvements compared to samples subjected to the standard biodegradation process using autoclaved wood chips.


2014 ◽  
Vol 8 (4) ◽  
pp. 46-55
Author(s):  
Qays M. Issa ◽  
Muna H. AL-joburi ◽  
Abdul-Kareem J. Hashim

Fifty Rhizopus spp. isolates were obtained from local natural habitat. The ability of inulinase production by these isolates was screened. The isolate RC-2 which isolated from composite plants was the highest inulinase producer on modified Czapek-Dox agar in primary screening. Secondary screening revealed that the same isolate was the highest production on Nakamura broth medium. Isolate was identified as Rhizopusoryzae. Measurements of reducing sugars in crude filtrate which represent the products of enzyme revealed that Rhizopusoryzae RC-2 produced inulinaseextracellular. The optimum culture conditions for inulinase production by solid state fermentation included a mixture of Jerusalem artichoke Helianthus tuberosus tuber with sugarcane Saccharum sp. bagasse with a ratio (1:1) as carbon source, 2.5% of corn steep liquor as nitrogen source, moisturizing ratio (3:1) (v:w) with tap water, the best inoculums rate was 2.5×105 spore/ml and incubation at (30)ºC for 4 days.


2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Abbas Akhavan Sepahy ◽  
Leila Jabalameli

Soil samples of Tehran jungle parks were screened for proteolytic Bacilli. Among eighteen protease producers one of the isolates obtained from Lavizan park, in north east of Tehran, was selected for further experimental studies. This isolate was identified as Bacillus sp. strain CR-179 based on partial sequencing of 16S rRNA. Various nutritional and environmental parameters affected protease production by Bacillus sp. strain CR-179. Protease production by this Bacillus cultivated in liquid cultures reached a maximum at 24 h, with levels of 340.908 U/mL. Starch and maltose were the best substrates for enzyme production while some pure sugars such as fructose, glucose, and sucrose could not influence production of protease. Among various organic nitrogen sources corn steep liquor, which is commercial, was found as the best substrate followed by yeast extract, whey protein, and beef extract. The optimal pH and optimal temperature of enzyme production were 8.0 and 45°C, respectively. Studies on enzymatic characterization revealed that crude protease showed maximum activity at pH 9.0 and 60°C, which is indicating the enzyme to be thermoalkaline protease.


2020 ◽  
Vol 8 (5) ◽  
pp. 1290-1294
Author(s):  
Manish Pant ◽  
PK Omre ◽  
TP Singh ◽  
Pratima Awasthi ◽  
Khan Chand ◽  
...  

2016 ◽  
Vol 703 ◽  
pp. 337-342
Author(s):  
Rong Hu Zhang ◽  
Jian Cheng Feng

A strain of mutant Streptococcus equi JC-63, which can produce high molecular weight hyaluronic acid, was obtained from compound mutation breeding of Streptococcus equi JC-0 using 5-Bromouracil, UV rays and nitrosoguanidine as mutagenic agents. After inoculation for 25 generations, Streptococcus equi JC-63 showed inheritance stability, but not hemolysis. The culture conditions for producing HMW-HA were optimized in a 1-L shake flask through multi-factor orthogonal tests. Results showed the optimum ratio of fermentation medium comprised 50 g/L sucrose, 80 g/L corn steep liquor, 10 g/L glucose, 2 g/L MgSO4, 2 g/L NaHCO3, 2 g/L Na2HPO4, and 0.1 g/L UTP. Under these fermentation conditions, the molecular weight of the produced HA was 2.76 × 106 Da, and HA yield reached 4.12 g/L.


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