Lignocellulosic biomasses, exhibit resistance to enzymatic hydrolysis due to the presence of lignin and hemicellulose. Ionic liquids proved their applicability in lignin degradation, however, ionic liquid removal has to be performed to proceed to hydrolysis. Therefore, this study reports an in situ hydrolysis of empty fruit bunches (EFB) that combined an ionic liquid (IL) pretreatment and enzymatic hydrolysis. For enzyme production, palm kernel cake (PKC) was used as the primary media for microbial cellulase (PKC-Cel) from Trichoderma reesei (RUTC30). The obtained enzyme exhibited a promising stability in several ionic liquids. Among few, in choline acetate [Cho]OAc, PKC-Cel retained 63.16 % of the initial activity after 6 h and lost only 10 % of its activity in 10 % IL/buffer mixture. Upon the confirmation of the PKC-Cel stability, EFB was subjected to IL-pretreatment followed by hydrolysis in a single step without further removal of the IL. The findings revealed that choline acetate [Cho]OAc and choline butyrate [Cho]Bu were among the best ILs used in the study since 0.332 ± 0.05 g glucose/g and 0.565 ± 0.08 g total reducing sugar/g EFB were obtained after 24 h of enzymatic hydrolysis. Compared to the untreated EFB, the amount of reducing sugar obtained after enzymatic hydrolysis increased by three-fold in the case of [Cho]OAc and [Cho]Bu, two-fold with [EMIM]OAc and phosphate-based ILs whereas the lowest concentration was obtained in [TBPH]OAc. Pretreatment of EFB with [Cho]OAc and [Cho]Bu showed significant differences in the morphology of EFB samples when observed with SEM. Analysis of the lignin, hemicellulose and hemicellulose showed that the total lignin content from the raw EFB was reduced from 37.8 ± 0.6 to 25.81 ± 0.35 % (w/w) upon employment of [Cho]OAc in the compatible system. The PKC-Cel from T. reesei (RUTC30) exhibited promising characteristics that need to be investigated further towards a single-step process for bioethanol production.
Information on the abiotic stress tolerance and ice-ice disease resistance properties of tissue-cultured Kappaphycus alvarezii is scarce and can pose a big hurdle to a wider use of tissue-cultured seaweed in the industry. Here, we reported on a study of seaweed-associated bacteria diversity in farmed and tissue-cultured K. alvarezii, and ice-ice disease resistance and elevated growth temperature tolerance of tissue-cultured K. alvarezii in laboratory conditions. A total of 40 endophytic seaweed-associated bacteria strains were isolated from 4 types of K. alvarezii samples based on their colony morphologies, Gram staining properties and 16S rRNA gene sequences. Bacteria strains isolated were found to belong to Alteromonas sp., Aestuariibacter sp., Idiomarina sp., Jejuia sp., Halomonas sp., Primorskyibacter sp., Pseudoalteromonas sp., Ruegeria sp., Terasakiella sp., Thalassospira sp. and Vibrio sp. Vibrio alginolyticus strain ABI-TU15 isolated in this study showed agar-degrading property when analyzed using agar depression assay. Disease resistance assay was performed by infecting healthy K. alvarezii with 105 cells/mL Vibrio sp. ABI-TU15. Severe ice-ice disease symptoms were detected in farmed seaweeds compared to the tissue-cultured K. alvarezii. Besides disease resistance, tissue-cultured K. alvarezii showed better tolerance to the elevated growth temperatures of 30 and 35 °C. In conclusion, our overall data suggests that tissue-cultured K. alvarezii exhibited better growth performance than farmed seaweeds when exposed to elevated growth temperature and ice-ice disease-causing agent.
Yeast cell death is triggered when essential nutrients such as potassium and lipid are limited but ammonium is in excess. When ammonium and glucose were maintained at 100% of the normal concentration while all the other essential nutrients in yeast nitrogen base (YNB) were reduced to 2%, yeast growth was halted by ammonium toxicity. Yeast started to grow again when either ammonium was also reduced to 2% or gluconate was added, but simultaneously adding gluconate as well as reducing all the nutrients except glucose 50-fold revived yeast growth to a greater extent, i.e. a quarter of the normal growth. Gluconate, as well as formate and alginate, stimulated yeast growth by buffering the drop in pH. Yeast cells were seemingly more susceptible to low pH under the nutrient-limited conditions, entering the stationary phase at pH higher than that of the normal condition. Carboxylate salts may prove a cost-efficient replacement for large proportions of the essential nutrients as yeast cells, in the presence of 2 mg ml-1 gluconate, could still achieve nearly 90% of the normal growth when cultured in only 10% of the normal YNB concentration.
The aim of the present study is to investigate the potential of magnetic field application as an alternative approach for controlling sludge bulking due to long sludge retention time (SRT) while enhancing nitrification efficiency upon the occurrence. Two sequencing batch reactors, reactor A (SBRA, magnetic field intensity 88.0 mT) and reactor B (SBRB, control) were operated under long SRT to induce the growth of filamentous microorganisms. The effect of magnetic field on nitrification, viz. ammonia-nitrogen (NH4-N) and nitrite removal, as well as biomass properties were studied under the sludge bulking condition. Results indicated that nitrification efficiency of SBRA was consistently higher with 90% NH4-N removal and 74-81% nitrite removal, which could be credited to the enhanced biomass properties of activated sludge due to the induced magnetic field. Metabolism activity and biodegradability of aerobic bacteria were also enhanced through the application of magnetic field, even under long SRT condition. This was evidenced by the average oxygen uptake rate (OUR) in SBRA that was higher with 11.7 ± 1.2 mg/L·h compared to SBRB with 9.5 ± 0.4 mg/L·h. Occurrence of filamentous sludge bulking was likewise minimized.
This study aimed to enhance production of polyhydroxybutyrate P(3HB) by a newly engineered strain of Cupriavidus necator NSDG-GG by applying response surface methodology (RSM). From initial experiment of one-factor-at-a-time (OFAT), glucose and urea were found to be the most significant substrates as carbon and nitrogen sources, respectively, for the production of P(3HB). OFAT experiment results showed that the maximum biomass, P(3HB) content, and P(3HB) concentration of 8.95 g/L, 76 wt%, and 6.80 g/L were achieved at 25 g/L glucose and 0.54 g/L urea with an agitation rate of 200 rpm at 30 °C after 48 h. In this study, RSM was applied to optimize the three key variables (glucose concentration, urea concentration, and agitation speed) at a time to obtain optimal conditions in a multivariable system. Fermentation experiments were conducted in shaking flask by cultivation of C. necator NSDG-GG using various glucose concentrations (10-50 g/L), urea concentrations (0.27-0.73 g/L), and agitation speeds (150-250 rpm). The interaction between the variables studied was analyzed by ANOVA analysis. The RSM results indicated that the optimum cultivation conditions were 37.70 g/L glucose, 0.73 g/L urea, and 200 rpm agitation speed. The validation experiments under optimum conditions produced the highest biomass of 12.84 g/L, P(3HB) content of 92.16 wt%, and P(3HB) concentration of 11.83 g/L. RSM was found to be an efficient method in enhancing the production of biomass, P(3HB) content, and P(3HB) concentration by 43, 21, and 74%, respectively.
The contribution of microbial depolymerase has received much attention because of its potential in biopolymer degradation. In this study, the P(3HB) depolymerase enzyme of a newly isolated Burkholderia cepacia DP1 from soil in Penang, Malaysia, was optimized using response surface methodology (RSM). The factors affecting P(3HB) depolymerase enzyme production were studied using one-variable-at-a-time approach prior to optimization. Preliminary experiments revealed that the concentration of nitrogen source, concentration of carbon source, initial pH and incubation time were among the main factors influencing the enzyme productivity. An increase of 9.4 folds in enzyme production with an activity of 5.66 U/mL was obtained using optimal medium containing 0.028% N of di-ammonium hydrogen phosphate and 0.31% P(3HB-co-21%4HB) as carbon source at the initial pH of 6.8 for 38 h of incubation. Moreover, the RSM model showed great similarity between predicted and actual enzyme production indicating a successful model validation. This study warrants the ability of P(3HB) degradation by B. cepacia DP1 in producing higher enzyme activity as compared to other P(3HB) degraders being reported. Interestingly, the production of P(3HB) depolymerase was rarely reported within genus Burkholderia. Therefore, this is considered to be a new discovery in the field of P(3HB) depolymerase production.
This investigation demonstrates an efficient method of propagation, short-term conservation, and germplasm exchange for Plectranthus amboinicus (Lour.) Spreng. encapsulated propagules. In vitro-derived shoot apices (shoot tips and nodal segments) which showed 100% survival on MS medium supplemented with 0.4 mg/L 6-benzylaminopurine were selected for encapsulation studies. Shoot apices measuring about 3-5 mm in size showed the ability to break the beads and exhibited 100% survival and regrowth. The combination of 3% (w/v) sodium alginate and 100 mM CaCl2 was found to be ideal for forming uniformally spherical beads, and successive preservation of encapsulated shoot apices into plantlets. The encapsulated shoot tips were relatively more effective than the nodal segments in terms of shoot growth and multiplication. Encapsulated shoot tips retained the ability to regrow (63.3%) for up to 40 days when maintained at 4 °C. Encapsulated shoot tips effectively converted into plantlets on agar medium (78%) and peat moss (58%) under in vitro conditions. Encapsulated shoot tips on agar medium showed a higher shoot regeneration (9.91 ± 0.15 shoots per explant) ability than the peat moss (5.71 ± 0.34 shoots per explant), while the highest rooting (12.16 ± 0.23 roots per explant) was observed on peat moss. Thus, calcium alginate encapsulation holds latent qualities that could be explored to develop a future alternative method of propagation, short-term storage and germplasm distribution for elite genotypes of Plectranthus sp.
In this study, a wound dressing based on polyurethane (PU) blended with copper sulphate nanofibers was developed using an electrospinning technique. The prepared PU and PU nanocomposites showed smooth fibers without any bead defects. The prepared nanocomposites showed smaller fiber (663 ± 156.30 nm) and pore (888 ± 70.93 nm) diameter compared to the pristine PU (fiber diameter 1159 ± 147.48 nm and pore diameter 1087 ± 62.51 nm). The interaction of PU with copper sulphate was evident in the infrared spectrum through hydrogen-bond formation. Thermal analysis displayed enhanced weight residue at higher temperature suggesting interaction of PU with copper sulphate. The contact angle measurements revealed the hydrophilic nature of the prepared nanocomposites (71° ± 2.309°) compared with pure PU (100° ± 0.5774°). The addition of copper sulphate into the PU matrix increased the surface roughness, as revealed in the atomic force microscopy (AFM) analysis. Mechanical testing demonstrated the enhanced tensile strength behavior of the fabricated nanocomposites (18.58 MPa) compared with the pristine PU (7.12 MPa). The coagulation assays indicated the enhanced blood compatibility of the developed nanocomposites [activated partial thromboplastin time (APTT)-179 ± 3.606 s and partial thromboplastin time (PT)-105 ± 2.646 s] by showing a prolonged blood clotting time compared with the pristine PU (APTT-147.7 ± 3.512 s and PT-84.67 ± 2.517 s). Furthermore, the hemolysis and cytotoxicity studies suggested a less toxicity nature of prepared nanocomposites by displaying low hemolytic index and enhanced cell viability rates compared with the PU membrane. It was observed that the fabricated novel wound dressing possesses better physicochemical and enhanced blood compatibility properties, and may be utilized for wound-healing applications.
An efficient callus induction and plant regeneration system has been developed using salt and heat as pre-treatment factors for three barley genotypes viz. BB-3, BB-6 and BHL-18. Different concentrations of NaCl (1.5, 2.5, 3.5, 4.5, 5.5 and 6.5 g/L) were used and its effects were determined on the basis of the viability of callus (CV), plant regeneration (PR), relative growth rate (RGR) and tolerance index (TI). The BB-6 showed highest performance on tolerance based on CV (14.72%), PR (7.69%), RGR (0.91%) and TI (0.42%) at 6.5 g/L NaCl. Various NaCl concentrations displayed significantly differences at P
This study aimed to determine influence of corn inclusion on glutathion peroxidase (GPx) activity, selected minerals concentration, and gene expression in sheep-fed palm kernel cake (PKC) and urea-treated rice straw. Twenty-seven of Dorper sheep were divided into three groups and fed a basal diet of (20% rice straw and 80% concentrate) with addition of ground corn at either 0% (T1), 5% (T2), or 10% (T3), respectively. After 120 days feeding trial, all animals were slaughtered and tissue samples of kidney, liver, and muscles were taken for enzyme and mineral analyses. The results showed that Cu concentration in the liver was lower treatment T3 compared to the control and T2. The serum activity of GPx was higher in T2 than in T3 at day 120 of experiment. Serum malondialdehyde (MDA) concentrations decreased at day 80 in sheep on T3, whereas MDA of liver increased linearly with increasing corn supplementation. The qRT-PCR analyses revealed significant up-regulation of ATP7A and MIa genes in T3, while hepatic Cu/Zn SOD, GPx1, and GPx4 mRNA showed a higher expression in lamb hepatocytes in T3 compared to those on T1. Present study results suggest that feeding PKC as basal diet can increase antioxidant activity, but cause liver dysfunction in sheep. Inclusion corn was found to regulate transcriptional levels of the GPx family and metallothionein genes. These genes may play a role in the antioxidant protection response and reduce incidence of toxicity associated with Cu.
The ability of gellan gum-immobilised cells of the heavy metal-tolerant bacterium Alcaligenes sp. AQ05-001 to utilise both heavy metal-free and heavy metal-polluted feathers (HMPFs) as substrates to produce keratinase enzyme was studied. Optimisation of the media pH, incubation temperature and immobilisation parameters (bead size, bead number, gellan gum concentration) was determined for the best possible production of keratinase using the one-factor-at-a-time technique. The results showed that the immobilised cells could tolerate a broader range of heavy metal concentrations and produced higher keratinase activity at a gellan gum concentration of 0.8% (w/v), a bead size of 3 mm, bead number of 250, pH of 8 and temperature of 30 °C. The entrapped bacterium was used repeatedly for ten cycles to produce keratinase using feathers polluted with 25 ppm of Co, Cu and Ag as substrates without the need for desorption. However, its inability to tolerate/utilise feathers polluted with Hg, Pb, and Zn above 5 ppm, and Ag and Cd above 10 ppm resulted in a considerable decrease in keratinase production. Furthermore, the immobilised cells could retain approximately 95% of their keratinase production capacity when 5 ppm of Co, Cu, and Ag, and 10 ppm of As and Cd were used to pollute feathers. When the feathers containing a mixture of Ag, Co, and Cu at 25 ppm each and Hg, Ni, Pb, and Zn at 5 ppm each were used as substrates, the immobilised cells maintained their operational stability and biological activity (keratinase production) at the end of 3rd and 4th cycles, respectively. The study indicates that HMPF can be effectively utilised as a substrate by the immobilised-cell system of Alcaligenes sp. AQ05-001 for the semi-continuous production of keratinase enzyme.
The halophilic genus Joostella is one of the least-studied genera in the family of Flavobacteriaceae. So far, only two species were taxonomically identified with limited genomic analysis in the aspect of application has been reported. Joostella atrarenae M1-2T was previously isolated from a seashore sample and it is the second discovered species of the genus Joostella. In this project, the genome of J. atrarenae M1-2T was sequenced using NovaSeq 6000. The final assembled genome is comprised of 71 contigs, a total of 3,983,942 bp, a GC ratio of 33.2%, and encoded for 3,416 genes. The 16S rRNA gene sequence of J. atrarenae M1-2T shows 97.3% similarity against J. marina DSM 19592T. Genome-genome comparison between the two strains by ANI, dDDH, AAI, and POCP shows values of 80.8%, 23.3%, 83.4%, and 74.1% respectively. Pan-genome analysis shows that strain M1-2T and J. marina DSM 19592T shared a total of 248 core genes. Taken together, strain M-2T and J. marina DSM 19592T belong to the same genus but are two different species. CAZymes analysis revealed that strain M1-2T harbors 109 GHs, 40 GTs, 5 PLs, 9 CEs, and 6 AAs. Among these CAZymes, while 5 genes are related to cellulose degradation, 12 and 24 genes are found to encode for xylanolytic enzymes and other hemicellulases that involve majorly in the side chain removal of the lignocellulose structure, respectively. Furthermore, both the intracellular and extracellular crude extracts of strain M1-2T exhibited enzymatic activities against CMC, xylan, pNPG, and pNPX substrates, which corresponding to endoglucanase, xylanase, β-glucosidase, and β-xylosidase, respectively. Collectively, description of genome coupled with the enzyme assay results demonstrated that J. atrarenae M1-2T has a role in lignocellulosic biomass degradation, and the strain could be useful for lignocellulosic biorefining.
Broad host range (BHR) expression vector is a vital tool in molecular biology research and application. Currently, most of the plasmid vectors used in Agrobacterium spp. are binary vectors that are designed for plant transformation, and very few are designed for expressing transgenes in Agrobacterium spp. Class 1 integrons are common genetic elements that allow for the efficient capture and expression of antibiotic resistance genes, especially in Gram-negative bacteria. One of its compound promoters, PcS + P2, was used in this study and has been reported to be the strongest class 1 integron constitutive promoter; it is referred to as "integron promoter" (P int) henceforth. Herein, we created two versions of isopropyl-d-thiogalactopyranoside (IPTG)-inducible promoters by substituting and/or inserting lacO sequence(s) into P int. These inducible promoters, which possess different degrees of stringency and inducibility, were used to construct two broad host range expression vectors (pWK102 and pWK103) based on the versatile pGREEN system. This allows them to be stably maintained and replicated in both Escherichia coli and Agrobacterium tumefaciens. Functional validation of these vectors was performed by the expression of the reporter gene, superfolder green fluorescent protein (sfGFP), which was cloned downstream of these promoters. Due to the strong induction and tunable expression of a transgene located downstream to the inducible integron promoter, these vectors may be useful for heterologous gene expression in both E. coli and A. tumefaciens, thus facilitating recombinant protein production and genetic studies in Gram-negative bacteria.
SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-023-03507-0.
In current era, majority of microRNA (miRNA) are being discovered through computational approaches which are more confined towards model plants. Here, for the first time, we have described the identification and characterization of novel miRNA in a non-model plant, Persicaria minor (P. minor) using computational approach. Unannotated sequences from deep sequencing were analyzed based on previous well-established parameters. Around 24 putative novel miRNAs were identified from 6,417,780 reads of the unannotated sequence which represented 11 unique putative miRNA sequences. PsRobot target prediction tool was deployed to identify the target transcripts of putative novel miRNAs. Most of the predicted target transcripts (mRNAs) were known to be involved in plant development and stress responses. Gene ontology showed that majority of the putative novel miRNA targets involved in cellular component (69.07%), followed by molecular function (30.08%) and biological process (0.85%). Out of 11 unique putative miRNAs, 7 miRNAs were validated through semi-quantitative PCR. These novel miRNAs discoveries in P. minor may develop and update the current public miRNA database.
With the rapid growth of the fruit industry worldwide, it is important to assess adulteration to ensure the authenticity and the safety of fruit products. The DNA barcoding approach offers a quick and accurate way of identifying and authenticating species. In this study, we developed reference DNA barcodes (rbcL, ITS2, and trnH-psbA) for 70 cultivated and wild tropical fruit species, representing 43 genera and 26 families. In terms of species recoverability, rbcL has a greater recoverability (100%) than ITS2 (95.7%) and trnH-psbA (88.6%). We evaluated the performance of these barcodes in species discrimination using similarity BLAST, phylogenetic tree, and barcoding gap analyses. The efficiency of rbcL, ITS2, and trnH-psbA in discriminating species was 80%, 100%, and 93.6%, respectively. We employed a multigene-tiered approach for species identification, with the rbcL region used for primary differentiation and ITS2 or trnH-psbA used for secondary differentiation. The two-locus barcodes rbcL + ITS2 and rbcL + trnH-psbA demonstrated robustness, achieving species discrimination rates of 100% and 94.3% respectively. Beyond the conventional species identification method based on plant morphology, the developed reference barcodes will aid the fruit agroindustry and trade, by making fruit-based product authentication possible.
SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-023-03848-w.
The present study investigates the cytotoxicity of hexagonal MgO nanoparticles synthesized via Amaranthus tricolor leaf extract and spherical MgO nanoparticles synthesized via Amaranthus blitum and Andrographis paniculata leaf extracts. In vitro cytotoxicity analysis showed that the hexagonal MgO nanoparticles synthesized from A. tricolor extract demonstrated the least toxicity to both diabetic and non-diabetic cells at 600 μl/ml dosage. The viability of the diabetic cells (3T3-L1) after incubation with varying dosages of MgO nanoparticles was observed to be 55.3%. The viability of normal VERO cells was 86.6% and this stabilized to about 75% even after exposure to MgO nanoparticles dosage of up to 1000 μl/ml. Colorimetric glucose assay revealed that the A. tricolor extract synthesized MgO nanoparticles resulted in ~ 28% insulin resistance reversal. A reduction in the expression of GLUT4 protein at 54 KDa after MgO nanopaSrticles incubation with diabetic cells was observed via western blot analysis to confirm insulin reversal ability. Fluorescence microscopic analysis with propidium iodide and acridine orange dyes showed the release of reactive oxygen species as a possible mechanism of the cytotoxic effect of MgO nanoparticles. It was inferred that the synergistic effect of the phytochemicals and MgO nanoparticles played a significant role in delivering enhanced insulin resistance reversal capability in adipose cells.
The current report assesses the efficiency of encapsulation-desiccation protocol to cryopreserve oil palm (Elaeis guineensis Jacq.) polyembryoids. Specifically identified polyembryoids, comprising of haustorium and torpedo-shaped structures, were encapsulated [comprising 3% (w/v) sodium alginate and 100 mM CaCl2]. Calcium alginate-encapsulated and sucrose-precultured polyembryoids were subjected to different spans of desiccation in a laminar air-flow cabinet, followed by freezing in liquid nitrogen. The effect of sucrose preculture (with gradual exposure to 0.3, 0.5, 0.75 and 1 M for 7 days) and dehydration periods (0-10 h) under sterile air-flow on post-freezing survival and regrowth of encapsulated polyembryoids were studied. Cryopreserved and thawed polyembryoids (initially precultured in sucrose, followed by 9 h air-desiccated to 23.3% moisture content) displayed the highest survival percentage (73.3%) and regeneration (of shoot, root and secondary somatic embryo) on Murashige and Skoog regrowth medium containing sucrose (0.3-1 M) and 0.2 mg/l 2,4-dichlorophenoxy acetic acid. In addition, ultrastructural study using scanning electron microscopy exhibited successful revival of cryopreserved polyembryoids, owing to retention of cellular membrane stability through optimized and protected (encapsulated) desiccation. The present study thus substantiates the potential of this encapsulation-desiccation procedure in cryopreservation of oil palm polyembryoids for long-term conservation programs.
Tree species in the Aquilarieae tribe of the Thymelaeaceae family produce agarwood, a natural product highly valued for its fragrance, but the species are under threat due to indiscriminate harvesting. For conservation of these species, molecular techniques such as DNA profiling have been used. In this study, we assessed cross-amplification of microsatellite markers, initially developed for three Aquilaria species (A.crassna, A.malaccensis, and A.sinensis), on ten other agarwood-producing species, including members of Aquilaria (A.beccariana, A.hirta, A.microcarpa, A.rostrata, A.rugosa, A.subintegra, and A.yunnanensis) and Gyrinops (G.caudata, G.versteegii, and G.walla), both from the Aquilarieae tribe. Primers for 18 out of the 30 microsatellite markers successfully amplified bands of expected sizes in 1 sample each of at least 10 species. These were further used to genotype 74 individuals representing all the 13 studied species, yielding 13 cross-amplifiable markers, of which only 1 being polymorphic across all species. At each locus, the number of alleles ranged from 7 to 23, indicating a rather high variability. Four markers had relatively high species discrimination power. Our results demonstrated that genetic fingerprinting can be an effective tool in helping to manage agarwood genetic resources by potentially supporting the chain-of-custody of agarwood and its products in the market.
Rhodothermaceae bacterium RA is a halo-thermophile isolated from a saline hot spring. Previously, the genome of this bacterium was sequenced using a HiSeq 2500 platform culminating in 91 contigs. In this report, we report on the resequencing of its complete genome using a PacBio RSII platform. The genome has a GC content of 68.3%, is 4,653,222 bp in size, and encodes 3711 genes. We are interested in understanding the carbohydrate metabolic pathway, in particular the lignocellulosic biomass degradation pathway. Strain RA harbors 57 glycosyl hydrolase (GH) genes that are affiliated with 30 families. The bacterium consists of cellulose-acting (GH 3, 5, 9, and 44) and hemicellulose-acting enzymes (GH 3, 10, and 43). A crude cell-free extract of the bacterium exhibited endoglucanase, xylanase, β-glucosidase, and β-xylosidase activities. The complete genome information coupled with biochemical assays confirms that strain RA is able to degrade cellulose and xylan. Therefore, strain RA is another excellent member of family Rhodothermaceae as a repository of novel and thermostable cellulolytic and hemicellulolytic enzymes.
Pineapple peel is a potential feedstock for the extraction of essential oil due to the presence of aromatic compounds. To extract the essential oil from pineapple peels, three different methods were applied, i.e., (1) hydro-distillation (HD); (2) hydro-distillation with enzyme-assisted (HDEA); and (3) supercritical fluid extraction (SFE). SFE had successfully produced an essential oil with the yield of 0.17% (w/w) together with 0.64% (w/w) of concrete, whereby the HD and HDEA had only produced hydrosols with the yield of 70.65% (w/w) and 80.65% (w/w), respectively. Parameters' optimization for HD (substrate to solvent ratio, temperature, and extraction duration) and HDEA (cellulase loading and incubation duration) significantly affected the hydrosol yield, but did not extract out the essential oil. This is because only SFE had successfully ruptured the oil gland after observed under the scanning electron microscope. The essential oil obtained from SFE composed of mainly propanoic acid ethyl ester (40.25%), lactic acid ethyl ester (19.35%), 2-heptanol (15.02%), propanol (8.18%), 3-hexanone (2.60%), and butanoic acid ethyl ester (1.58%). In overall, it can be concluded that the SFE had successfully extracted the essential oil as compared to the HD and HDEA methods.