Strategies for the continuous production of ligninolytic enzymes in fixed and fluidised bed bioreactors

Moreira, Marı́a Teresa; Palma, C.; Lema, Juan M.

doi:10.1016/s0168-1656(98)00154-0

Cited by 54 publications

(21 citation statements)

References 48 publications

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“…A systematic screening of ligninolytic fungi [54] reported that lignin was preferentially degraded from wheat straw by P. ostreatus. White rot fungi, of which P. ostreatus is an example, possess unique ligninolytic enzymes that completely degrade lignin to CO 2 and H 2 O [55]. These extracellular enzymes depolymerize lignin through the C-C bond and ether bond cleavage reactions [56], and prevent repolymerization between fragmented units [57].…”

Section: Ligninmentioning

confidence: 99%

Co-Substrating of Peanut Shells with Cornstalks Enhances Biodegradation by Pleurotus ostreatus

FN¹,

Yusuf²

2016

J Bioremed Biodeg

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IntroductionPeanut shells (PS) are abundant agro-industrial waste products that are recalcitrant to degradation under natural conditions [1]. The increasing expansion of peanut production has led to accumulation of large quantities of these shells all over the world. In the US alone, peanut production increased by 45% between 2011 and 2012, bringing production to 3.04 million metric tons [2]. Globally, 45.6 million metric tons of peanuts are produced annually [3]. It has been estimated that for every kg of peanuts produced, 230-300 g of peanut shells are generated [4]. Therefore, as much as 13.7 million metric tons of peanut shells are churned out every year, most of which are dumped into the environment or burned [5,6]. Peanut shells are a renewable resource that could be targeted for purposeful use in the food, feed, paper and bioenergy industries. However, as yet, few if any value-added uses exist for them [7].Over the years, various attempts to utilize peanut shells have been made. Small fractions were incorporated into animal feed, especially for cattle [8], while some authors have experimented on their use as dietary fiber for humans [9]. Other non-food research trials include uses in pulp production [10], feedstock for bioethanol production [11,12], particle board component [13], mulch and activated charcoal [7]. However, the major drawback to their use in large scale industrial operations is the high lignin content.Much like other agricultural lignocellulolysic biomass, peanut shells are composed mainly of lignin, cellulose and hemicellulose. Lignin, a complex polymer, is the most recalcitrant component of plant biomass [14] and binds tightly to, and provides a physical seal around, cellulose and hemicellulose [11,[15][16][17][18], thereby protecting them against attack by hydrolytic enzymes. The restricted bioavailability of these sugars and other components is thought to be largely physical, with lignin molecules reducing the surface area available to enzymatic penetration and activity [19]. In order to gain access to the sugars in cellulose and AbstractWorld consumption of peanuts has increased tremendously, resulting in abundance of peanut shell waste. The high lignin content of peanut shells limits their bioconversion to useful products or recycling. Therefore, the synergy in co-substrating peanut shells (PS) and cornstalks (CS) to enhance biodegradation was evaluated. Various compositions of peanut shells and cornstalks (% dry weight) herein called co-substrate -90PS:10CS, 75PS:25CS, 50PS:50CS, 25PS:75CS, 10PS:90CS, and two controls Cont1-100PS and Cont2-100CS were studied under solid state fermentation (SSF) with a white rot fungus, Pleurotus ostreatus for 120 days. A two-factorial experiment in a completely randomized design (CRD) was used. Results showed that substrate composition and fermentation time were important variables in substrate degradation. Lignin degradation, losses in organic matter, cellulose and hemicellulose increased with time. Increasing the composition of CS in co-substrates...

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Section: Ligninmentioning

confidence: 99%

Co-Substrating of Peanut Shells with Cornstalks Enhances Biodegradation by Pleurotus ostreatus

FN¹,

Yusuf²

2016

J Bioremed Biodeg

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“…But for the application in large scale treatment, it has been impeded of owing to lack of an appropriate reactor system capable of coping with relatively slow fungal degradation, loss of extracellular enzymes and mediator with discharged water [33,49].…”

Section: Introductionmentioning

confidence: 99%

Decolorization of synthetic melanoidins-containing wastewater by a bacterial consortium

Jiranuntipon

Chareonpornwattana

Damronglerd

et al. 2008

J Ind Microbiol Biotechnol

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The presence of melanoidins in molasses wastewater leads to water pollution both due to its dark brown color and its COD contents. In this study, a bacterial consortium isolated from waterfall sediment was tested for its decolorization. The identification of culturable bacteria by 16S rDNA based approach showed that the consortium composed of Klebsiella oxytoca, Serratia mercescens, Citrobacter sp. and unknown bacterium. In the context of academic study, prevention on the difficulties of providing effluent as well as its variations in compositions, several synthetic media prepared with respect to color and COD contents based on analysis of molasses wastewater, i.e., Viandox sauce (13.5% v/v), caramel (30% w/v), beet molasses wastewater (41.5% v/v) and sugarcane molasses wastewater (20% v/v) were used for decolorization using consortium with color removal 9.5, 1.13, 8.02 and 17.5%, respectively, within 2 days. However, Viandox sauce was retained for further study. The effect of initial pH and Viandox concentration on decolorization and growth of bacterial consortium were further determined. The highest decolorization of 18.3% was achieved at pH 4 after 2 day of incubation. Experiments on fresh or used medium and used or fresh bacterial cells, led to conclusion that the limitation of decolorization was due to nutritional deficiency. The effect of aeration on decolorization was also carried out in 2 L laboratory-scale suspended cell bioreactor. The maximum decolorization was 19.3% with aeration at KLa = 2.5836 h -1 (0.1 vvm).

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“…Mediators like 1-hydroxybenzotriazole, acetosyringone, and syringaldehyde were successfully adopted in combination with laccases in the biochemical bleaching of paper pulp and in the degradation of textile fibers. In contrast, the Mediator p-coumaric acid, for example, was less suitable for such applications (Moreira et al 1998;Pandey et al 2000;Lund and Felby 2001;Camarero et al 2004;Chakar and Ragauskas 2004;Rochefort et al 2004;Hakala et al 2005;Ibarra et al 2006;Camarero et al 2007;Gutiérrez et al 2007;Vivekanand et al 2008). A positive effect of the Mediator 4-hydroxy benzoic acid (HBA) in the modifying of paper is described by Chandra et al (2004).…”

Section: Introductionmentioning

confidence: 99%

Studies of enzymatic oxidation of TMP-fibers and lignin model compounds by a Laccase–Mediator-System using different 14C and 13C techniques

et al. 2011

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In this work, the results of the enzymatic oxidation of TMP-fibers (thermomechanical pulp) and a well-structured lignin model compound, the dehydropolymer (DHP), were investigated by different 14 C and 13 C methods, caused by a Laccase-Mediator-System (LMS). These methods are the nuclear magnetic resonance spectroscopy ( 13 C-NMR) with DHP (unmarked) and the determination of the 14 CO 2 release of 14 C-marked DHP and TMP-fibers. The 13 C-NMR measurements were chosen to analyze the structural changes of the LMS-treated DHP model compounds and TMP-fibers qualitatively and quantitatively. The data of 14 CO 2 release give an explanation of the demethylation of DHP and TMP-fibers. The effect of the LMS is shown by comparing the results in respect of DHP and TMP-fibers, which were only treated with laccase and of an inactivated LMS as the control. Comparing the results of the 13 C-NMR method, in particular the use of the Mediator during the enzymatical treatment, showed significant changes in the structure of the DHP. Also, the TMP-fibers were materially influenced by the LMS. The analysis of the 14 CO 2 release data of the 14 C-marked DHP and TMP-fibers revealed that the rate of 14 CO 2 increases in the 14 C-2 atom as well as in the O 14 CH 3 group within the first hour of Laccase-Mediator incubation. Therefore, the 14 CO 2 release from the DHP was higher than from the TMP-fibers.

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Strategies for the continuous production of ligninolytic enzymes in fixed and fluidised bed bioreactors

Cited by 54 publications

References 48 publications

Co-Substrating of Peanut Shells with Cornstalks Enhances Biodegradation by Pleurotus ostreatus

Co-Substrating of Peanut Shells with Cornstalks Enhances Biodegradation by Pleurotus ostreatus

Decolorization of synthetic melanoidins-containing wastewater by a bacterial consortium

Studies of enzymatic oxidation of TMP-fibers and lignin model compounds by a Laccase–Mediator-System using different 14C and 13C techniques

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