Tannase production by Lactobacillus sp. ASR-S1 under solid-state fermentation

Microbial tannases: biosynthesis, purification, characterization and potential industrial applications

Tannases are a family of esterases that catalyze the hydrolysis of ester and depside bonds present in hydrolyzable tannins to release glucose and gallic acid. This enzyme is widely spread in animals, plants, and microbes. In particular, fungi and bacteria are the major sources of tannase. In recent years, this enzyme has drawn the attention of investigators owing to its widespread emerging applications in different food, beverage, animal feed, pharmaceutical, and tannery effluent degradation processes. During the last decade, over-expression of the tannase gene and structural activity has gained momentum. This research focused on microbial tannases, which have sparked interest due to their various properties. The current study investigates the sources of tannase-producing microorganisms, the mechanisms of tannin metabolism, and the microbe's degradation of natural tannins. Furthermore, researchers proposed tannase's biochemical properties, cloning, expression, and structural construction. This review will help better understand microbial tannases for several important industrial and environmental applications.

Antioxidant and in vitro cosmeceutical activities of chestnut inner shell fermented by Monascus kaoliang

Chestnut inner shell (CIS) was fermented at 30 °C for 12 day using Monascus kaoliang, either in solid or submerged state, and alcohol extracts (70% ethanol) of the fermented CIS were examined for their antioxidant (total phenol content and diphenylpicrylhydrazyl radical scavenging activity) and in vitro cosmeceutical activities (tyrosinase and elastase inhibitory activities). Both activities were significantly increased by the M. kaoliang-fermentation, more apparently by submerged fermentation (SMF) than by solid-state fermentation (SSF). The cosmeceutical activity reached its maximum value on the 3rd day of fermentation. The residual amounts of phenolic acids and catechins in the CIS extracts were increased by the fermentation, up to 395.0 and 344.3 µg/g, respectively. More phenolic acids were produced by SMF than SSF, whereas more catechins were produced by SSF than SMF. Therefore, SMF using M. kaoliang was an efficient process for the utilization of CIS as a source of cosmeceuticals.

A comprehensive review on tannase: Microbes associated production of tannase exploiting tannin rich agro-industrial wastes with special reference to its potential environmental and industrial applications

Microorganisms have been used for the production of various enzymes, including inducible tannase for various industrial and environmental applications. Tannases have lot of potential to convert hydrolysable tannins to gallic acid, which is one of the important industrial and therapeutic significant molecules whose demand is over 10000 tons per year. Tannins invariably occur in angiosperms, gymnosperms and pteridophytes, and predominantly present in various parts of plants such as, leaves, roots, bark and fruit. Furthermore, tannery effluents are frequently loaded with significant levels of tannic acid. Tannase can be effectively used to decrease tannin load in the toxic tannery effluent thus providing the opportunity to minimize the operational cost. Over the past three decades, tannase from microbial sources has been proposed for the degradation of natural tannins. The availability of various agro-industrial residues paves a way for maximum utilization of tannase production for the degradation of tannin and eventually the production of gallic acid. In this review, an illustrative and comprehensive account on tannase from microbial source for current day applications is presented. The present review emphasises on up-to-date microbial sources of tannases, biochemical properties, optimization of tannase production in solid state and submerged fermentation and its industrial and environmental applications.

Lactobacillus plantarum as feed additive to improvement in vitro ruminal biofermentation and digestibility of some tropical tree leaves

AIM

This study was performed to investigate the effects of Lactobacillus plantarum (LP) on the in vitro gas production (GP) kinetics and ruminal fermentation parameter of three species of tropical forage Ziziphus mauritiana, Acacia victoriae and Moringa oleifera.

METHODS AND RESULTS

Treatments were (i) Z. mauritiana (Z) without LP (-ZLP), (ii) Z. mauritiana (Z) with LP (+ZLP), (iii) A. victoriae (A) without LP (-ALP), (4) A. victoriae (A) with LP (+ALP), (5) M. oleifera (M) without LP (-MLP) and (6) M. oleifera (M) with LP (+MLP). The LP was used at 0·5 Mcfarland (1·5 × 10⁸ colony-forming unit per millilitre (CFU per ml)). Kinetic of GP (GP from the fermentable fraction [b], GP rate [c] and lag phase [L]) and GP were affected (P < 0·05) by plant species and LP. The highest value of b, c and GP were observed in +MLP treatment compared with other treatments. The lowest value of L was observed for the +ZLP treatment compared with other treatments. The GP and fermentation parameter included organic matter digestibility (OMD), metabolizable energy (ME) content, microbial CP (MCP) and truly degraded substrate (TDS) were affected by plant species and LP supplementation. The highest OMD, ME, TDS and MCP values were observed in +MLP treatment. At different incubation times, the highest amount of ammonia-N was observed in treatment +MLP compared with other treatments. Under the influence of experimental treatments (effect of plant species and LP), the highest concentrations of total volatile fatty acids, acetate and acetate to propionate ratio were observed in treatments +MLP, +ALP and +ALP, respectively. Concentrations of propionate, iso-butyrate, n-valerate and iso-valerate were affected by plant species, and the highest levels were observed in -ZLP, +MLP, -MLP and +MLP tretments, respectively.

CONCLUSIONS

The use of LP as a microbial additive had a positive effect on the in vitro digestibility and ruminal fermentation of tannins-rich tropical plants. Results suggest that dietary LP inclusion could be an option to improve ruminant energy utilization efficiency of tannins-rich tropical plants.

SIGNIFICANCE AND IMPACT OF THE STUDY

Regardless the effect of the forage species, the use of LP as a microbial additive improved GP and kinetics and also increased OMD, TDS, MCP and enhanced the total in vitro ruminal VFAs production.

Effect of replacing alfalfa hay with Leucaena leucocephala (L. Leucocephala) leaves on in vitro gas production, digestibility and in situ degradability in buffalo

. This study was performed to investigate the effect of replacing alfalfa hay by L. leucocephala leaves in proportions of 25, 50 and 100% on in vitro gas production (GP) parameter, digestibility and in situ degradability in buffalo. Results showed that the volume of GP at 2 to 12 hours after incubation was significantly affected by replacing alfalfa hay with L. leucocephala leaves. In vitro digestibility of organic matter (OMD) differed significantly between treatment as it declined by increasing the alfalfa hay substitution rate from 25 to 100%. The microbial crude protein (MCP) differed significantly between treatments and was the greatest of 589 and 599 mg g-1 of dry matter (DM) when L. leucocephala leaves replaced alfalfa hay at 25 and 50%. The in vitro digestibility of DM (IVDMD) increased significantly at 50% L. leucocephala replacement rate. Moreover, substituting alfalfa hay by L. leucocephala had a significant effect on the in situ degradability parameters. The insoluble but potentially degradable fraction (B) and potential of degradability (A+B) significantly increased for treatment contain 50% L. leucocephala leaves. The effective degradability (ED) was significantly different between dietary treatments and was the greatest when alfalfa hay was replaced by 25 and 50% L. leucocephala. In conclusion, L. leucocephala leaves can substitute 25 to 50% of dietary alfalfa hay in buffalo rations without effect on rumen efficiency.

A Comprehensive Review on Valorization of Agro-Food Industrial Residues by Solid-State Fermentation

Agro-food industrial residues (AFIRs) are generated in large quantities all over the world. The vast majority of these wastes are lignocellulosic wastes that are a source of value-added products. Technologies such as solid-state fermentation (SSF) for bioconversion of lignocellulosic waste, based on the production of a wide range of bioproducts, offer both economic and environmental benefits. The versatility of application and interest in applying the principles of the circular bioeconomy make SSF one of the valorization strategies for AFIRs that can have a significant impact on the environment of the wider community. Important criteria for SSF are the selection of the appropriate and compatible substrate and microorganism, as well as the selection of the optimal process parameters for the growth of the microorganism and the production of the desired metabolites. This review provides an overview of the management of AFIRs by SSF: the current application, classification, and chemical composition of AFIRs; the catalytic function and potential application of enzymes produced by various microorganisms during SSF cultivation on AFIRs; the production of phenolic compounds by SSF; and a brief insight into the role of SSF treatment of AFIRs for feed improvement and biofuel production.

Optimization of process conditions for tannin content reduction in cassava leaves during solid state fermentation using Saccharomyces cerevisiae

Cassava leaves are a crucial source of alternative protein resources for both humans and livestock in developing societies in African and Asian countries that do not have easy access to available protein sources. Hence, cassava has the capacity to promote the economic development of these countries and provide food security. However, it has some disadvantages due to the anti-nutrient compounds present in its tissues, which limits the nutritional value of cassava leaves. Thus, proper processing of cassava leaves is essential in order to reduce the anti-nutrients to a safer limit before utilization. This study focuses on reducing the tannin content of cassava leaves during solid-state fermentation using Saccharomyces cerevisiae. In addition, the Box-Behnken design of the Response Surface Methodology was applied to optimize various process parameters, such as carbon concentration, nitrogen concentration, moisture content, and incubation time for maximum reduction of tannin content in cassava leaves. A quadratic model was developed for the reduction of tannin content, which resulted in a perfect fit of the experimental data (p < 0.01). The optimal conditions were found at 1.4% (w/w) of carbon concentration, 0.55% (w/w) of nitrogen concentration, 57% (v/w) moisture content, and an incubation time of 96 h. The minimum tannin content obtained under these conditions was 0.125%, which indicated a reduction of 89.32 % in tannin content. Conversely, the protein content was increased with a further increase in fermentation time from 24 to 96 h (from 10.08 to 14.11-16.07 %). Furthermore, the ability of Saccharomyces cerevisiae to produce tannase under solid-state fermentation of cassava leaves was also studied. The maximum yield was obtained with an enzyme activity of 0.53 U/gds after 72 h of incubation.

Modeling and optimization of tannase production with Triphala in packed bed reactor by response surface methodology, genetic algorithm, and artificial neural network

In this research, optimization of the production medium to enhance tannase production by Bacillus gottheilii M2S2 in laboratory-scale packed bed reactor was studied. Amount of substrate Triphala, moisture content, aeration rate, and fermentation period was chosen for optimization study. During one variable at a time optimization, the highest tannase activity of 0.226 U/gds was shown with Triphala as a substrate at the fermentation period of 32 h. Furthermore, the optimum conditions predicted by response surface methodology (RSM) and genetic algorithm (GA) were found to be 11.532 g of substrate Triphala, 47.071% of the moisture content, and 1.188 L/min of an aeration rate with uppermost tannase activity of 0.262 U/gds. In addition, the single hidden layer feedforward neural network (SLFNN) and the radial basis function neural network (RBFNN) of an artificial neural network (ANN) were adopted to compare the prediction performances of the RSM and GA. It revealed that the ANN models (SLFNN, R ² = 0.9930; and RBFNN, R ² = 0.9949) were better predictors than the RSM (R ² = 0.9864). Finally, the validation experiment exhibited 0.265 U/gds of tannase activity at the optimized conditions, which is an 11-fold increase compared to unoptimized media in shake flask.

Solid state fermentation of Bacillus gottheilii M2S2 in laboratory-scale packed bed reactor for tannase production

Production of tannase was performed in packed bed reactor filled with an inert support polyurethane foam (PUF) using Bacillus gottheilii M2S2. The influence of process parameters such as fermentation time (24-72 h), tannic acid concentration (0.5-2.5% w/v), inoculum size (7-12% v/v), and aeration rate (0-0.2 L/min) on tannase production with PUF were analyzed using one variable at a time (OVAT) approach. The outcome of OVAT was optimized by central composite design. Based on the statistical investigation, the proposed mathematical model recommends 1% (w/v) of tannic acid, 10% (v/v) of inoculum size and 0.13 L/min of aeration rate for maximum production (76.57 ± 1.25 U/L). The crude enzyme was purified using ammonium sulfate salt precipitation method followed by dialysis. The biochemical properties of partially purified tannase were analyzed and found the optimum pH (4.0), temperature (40 °C) for activity, and K_m (1.077 mM) and V_max (1.11 µM/min) with methyl gallate as a substrate. Based on the SDS-PAGE analysis, tannase exhibited two bands with molecular weights of 57.5 and 42.3 kDa. Briefly, the partially purified tannase showed 4.2 fold increase (63 ± 1.60 U/L) in comparison to the submerged fermentation and the production of tannase was validated by using NMR spectrometer.

Production of poly(β-l-malic acid) by Aureobasidium pullulans HA-4D under solid-state fermentation

Poly(β-l-malic acid) (PMA) production by Aureobasidium pullulans HA-4D was carried out through solid-state fermentation (SSF) using agro-industrial residues. Maximum PMA production (75.4mg/g substrate) was obtained from a mixed substrate of sweet potato residue and wheat bran (1:1, w/w) supplemented with NaNO₃ (0.8%, w/w) and CaCO₃ (2%, w/w), with an initial moisture content of 70% and inoculum size of 13% (v/w) for 8days. Repeated-batch SSF was successfully conducted for 5 cycles with a high productivity. The scanning electron microscopy showed that the yeast-like cells of A. pullulans HA-4D could grow well on the solid substrate surface. Moreover, the cost analysis showed that the unit price of PMA in SSF was much lower than that of SmF. This is the first report on PMA production via SSF, and this study provided a new method to produce PMA from inexpensive agro-industrial residues.

Evaluation of model parameters for growth, tannic acid utilization and tannase production in Bacillus gottheilii M2S2 using polyurethane foam blocks as support

Production of tannase from B. gottheilii M2S2 was studied under solid-state fermentation with an optimized medium consisting of polyurethane foam matrix of dimension 40 × 40 × 5 mm, impregnated with a liquid medium comprising (w/v): 4% tannic acid; 2% NH₄NO₃; 0.1% KH₂PO₄; 0.2% MgSO₄; 0.1% NaCl and 0.05% CaCl₂·2H₂O in distilled water, having a pH of 4.7. Maximum tannase production of 56.87 U/L was obtained after 32 h of fermentation at 32 °C in static condition. This study deals with the evaluation of unstructured kinetic models to understand the behavior of biomass, tannase production and tannic acid degradation, with the fermentation time. The growth rate of B. gottheilii M2S2 was 0.0703 h^-1 at 32 h of fermentation. Product (Y_x/s) and biomass yield (Y_p/s) coefficients were estimated as 1.77 U/g of tannic acid and 0.276 g of biomass/g of tannic acid. All the kinetic constants µ, α, β, m and n were evaluated using MATLAB 2015Rb program. The experimental and model-generated data showed a good correlation, which indicated that these models will describe tannase production and fermentation process.

Application of methanol and sweet potato vine hydrolysate as enhancers of citric acid production by Aspergillus niger

Background

Agricultural waste is as an alternative low-cost carbon source or beneficial additives which catch most people’s eyes. In addition, methanol and sweet potato vine hydrolysate (SVH) have been reported as the efficient enhancers of fermentation according to some reports. The objective of the present study was to confirm SVH as an efficient additive in CA production and explore the synergistic effects of methanol and SVH in fermentation reactions.

Results

The optimal fermentation conditions resulted in a maximum citric acid concentration of 3.729 g/L. The final citric acid concentration under the optimized conditions was increased by 3.6-fold over the original conditions, 0.49-fold over the optimized conditions without methanol, and 1.8-fold over the optimized conditions in the absence of SVH. Kinetic analysis showed that Q_p, Y_p/s, and Y_x/s in the optimized systems were significantly improved compared with those obtained in the absence of methanol or SVH. Further, scanning electron microscopy (SEM) revealed that methanol stress promoted the formation of conidiophores, while SVH could neutralize the effect and prolong Aspergillus niger vegetative growth. Cell viability analysis also showed that SVH might eliminate the harmful effects of methanol and enhance cell membrane integrity.

Conclusions

SVH was a superior additive for organic acid fermentation, and the combination of methanol and SVH displayed a significant synergistic effect. The research provides a preliminary theoretical basis for SVH practical application in the fermentation industry.

Employment of Near Full-Length Ribosome Gene TA-Cloning and Primer-Blast to Detect Multiple Species in a Natural Complex Microbial Community Using Species-Specific Primers Designed with Their Genome Sequences

It remains an unsolved problem to quantify a natural microbial community by rapidly and conveniently measuring multiple species with functional significance. Most widely used high throughput next-generation sequencing methods can only generate information mainly for genus-level taxonomic identification and quantification, and detection of multiple species in a complex microbial community is still heavily dependent on approaches based on near full-length ribosome RNA gene or genome sequence information. In this study, we used near full-length rRNA gene library sequencing plus Primer-Blast to design species-specific primers based on whole microbial genome sequences. The primers were intended to be specific at the species level within relevant microbial communities, i.e., a defined genomics background. The primers were tested with samples collected from the Daqu (also called fermentation starters) and pit mud of a traditional Chinese liquor production plant. Sixteen pairs of primers were found to be suitable for identification of individual species. Among them, seven pairs were chosen to measure the abundance of microbial species through quantitative PCR. The combination of near full-length ribosome RNA gene library sequencing and Primer-Blast may represent a broadly useful protocol to quantify multiple species in complex microbial population samples with species-specific primers.

Improved production of tannase by Klebsiella pneumoniae using Indian gooseberry leaves under submerged fermentation using Taguchi approach

Tannase (tannin acyl hydrolase E.C 3.1.1.20) is an inducible, largely extracellular enzyme that causes the hydrolysis of ester and depside bonds present in various substrates. Large scale industrial application of this enzyme is very limited owing to its high production costs. In the present study, cost effective production of tannase by Klebsiella pneumoniae KP715242 was studied under submerged fermentation using different tannin rich agro-residues like Indian gooseberry leaves (Phyllanthus emblica), Black plum leaves (Syzygium cumini), Eucalyptus leaves (Eucalyptus glogus) and Babul leaves (Acacia nilotica). Among all agro-residues, Indian gooseberry leaves were found to be the best substrate for tannase production under submerged fermentation. Sequential optimization approach using Taguchi orthogonal array screening and response surface methodology was adopted to optimize the fermentation variables in order to enhance the enzyme production. Eleven medium components were screened primarily by Taguchi orthogonal array design to identify the most contributing factors towards the enzyme production. The four most significant contributing variables affecting tannase production were found to be pH (23.62 %), tannin extract (20.70 %), temperature (20.33 %) and incubation time (14.99 %). These factors were further optimized with central composite design using response surface methodology. Maximum tannase production was observed at 5.52 pH, 39.72 °C temperature, 91.82 h of incubation time and 2.17 % tannin content. The enzyme activity was enhanced by 1.26 fold under these optimized conditions. The present study emphasizes the use of agro-residues as a potential substrate with an aim to lower down the input costs for tannase production so that the enzyme could be used proficiently for commercial purposes.

Screening and Characterization of Cold-Active β-Galactosidase Producing Psychrotrophic Enterobacter ludwigii from the Sediments of Arctic Fjord

Low-temperature-tolerant microorganisms and their cold-active enzymes could be an innovative and invaluable tool in various industrial applications. In the present study, bacterial isolates from the sediment samples of Kongsfjord, Norwegian Arctic, were screened for β-galactosidase production. Among the isolates, KS25, KS85, KS60, and KS92 have shown good potential in β-galactosidase production at 20 °C. 16SrRNA gene sequence analysis revealed the relatedness of the isolates to Enterobacter ludwigii. The optimum growth temperature of the isolate was 25 °C. The isolate exhibited good growth and enzyme production at a temperature range of 15-35 °C, pH 5-10. The isolate preferred yeast extract and lactose for the maximum growth and enzyme production at conditions of pH 7.0, temperature of 25 °C, and agitation speed of 100 rpm. The growth and enzyme production was stimulated by Mn²⁺ and Mg²⁺ and strongly inhibited by Zn²⁺, Ni²⁺, and Cu⁺. β-Galactosidases with high specific activity at low temperatures are very beneficial in food industry to compensate the nutritional problem associated with lactose intolerance. The isolate exhibited a remarkable capability to utilize clarified whey, an industrial pollutant, for good biomass and enzyme yield and hence could be well employed in whey bioremediation.

The highest inhibition coefficient of phenol biodegradation using an acclimated mixed culture

In this study a membrane biological reactor (MBR) was operated at 25 ± 1 °C and pH = 7.5 ± 0.5 to treat synthetic wastewater containing high phenol concentrations. Removal efficiencies of phenol and chemical oxygen demand (COD) were evaluated at four various hydraulic retention times (HRTs) of 24, 12, 8, and 4 hours. The removal rate of phenol (5.51 kg-Phenol kg-VSS(-1) d(-1)), observed at HRT of 4 h, was the highest phenol degradation rate in the literature. According to COD tests, there were no significant organic matter in the effluent, and phenol was degraded completely by mixed culture. Substrate inhibition was calculated from experimental growth parameters using the Haldane, Yano, and Edward equations. The results show that the Haldane equation is fitted to the experimental data in an excellent manner. Kinetic parameters were derived by nonlinear regression with a correlation coefficient (R(2)) of 0.974. The values for Haldane constants μmax, Ks, and Ki were 0.3085 h(-1), 416 mg L(-1) and 1,886 mg L(-1), respectively. The Ki value is the highest value obtained for mixed cultures degrading phenol under batch conditions.

Optimization of tannase production by a novel Klebsiella pneumoniae KP715242 using central composite design

A novel tannase producing bacterial strain was isolated from rhizospheric soil of Acacia species and identified as Klebsiella pneumoniae KP715242. A 3.25-fold increase in tannase production was achieved upon optimization with central composite design using response surface methodology. Four variables namely pH, temperature, incubation period, and agitation speed were used to optimize significant correlation between the effects of these variables on tannase production. A second-order polynomial was fitted to data and validated by ANOVA. The results showed a complex relationship between variables and response given that all factors were significant and could explain 99.6% of the total variation. The maximum production was obtained at 5.2 pH, 34.97 °C temperature, 103.34 rpm agitation speed and 91.34 h of incubation time. The experimental values were in good agreement with the predicted ones and the models were highly significant with a correlation coefficient (R²) of 0.99 and a highly significant F-value of 319.37.

Screening a strain of Aspergillus niger and optimization of fermentation conditions for degradation of aflatoxin B₁

Aflatoxin B₁, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1) was able to degrade aflatoxin B₁ after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis on the basis of 18S rDNA, could remove 26.3% of aflatoxin B₁ after 48 h of fermentation in nutrient broth (NB). Optimization of fermentation conditions for aflatoxin B₁ degradation by selected Aspergillus niger was also performed. These results showed that 58.2% of aflatoxin B₁ was degraded after 24 h of culture under the optimal fermentation conditions. The aflatoxin B₁ degradation activity of Aspergillus niger supernatant was significantly stronger than cells and cell extracts. Furthermore, effects of temperature, heat treatment, pH, and metal ions on aflatoxin B₁ degradation by the supernatant were examined. Results indicated that aflatoxin B₁ degradation of Aspergillus niger is enzymatic and this process occurs in the extracellular environment.

Biosynthesis, structural architecture and biotechnological potential of bacterial tannase: a molecular advancement

Tannin-rich materials are abundantly generated as wastes from several agroindustrial activities. Therefore, tannase is an interesting hydrolase, for bioconversion of tannin-rich materials into value added products by catalyzing the hydrolysis of ester and depside bonds and unlocked a new prospect in different industrial sectors like food, beverages, pharmaceuticals, etc. Microorganisms, particularly bacteria are one of the major sources of tannase. In the last decade, cloning and heterologous expression of novel tannase genes and structural study has gained momentum. In this article, we have emphasized critically on bacterial tannase that have gained worldwide research interest for their diverse properties. The present paper delineate the developments that have taken place in understanding the role of tannase action, microbial sources, various cultivation aspects, downstream processing, salient biochemical properties, structure and active sites, immobilization, efforts in cloning and overexpression and with special emphasis on recent molecular and biotechnological achievements.

Studies on extraction of mannanase enzyme by Aspergillus terreus SUK-1 from fermented palm kernel cake

Microbial mannanases have become biotechnologically important in industry but their application is limited due to high production cost. In presents study, the extraction of mannanase from fermented Palm Kernel Cake (PKC) in the Solid State Fermentation (SSF) was optimized. Local isolate of Aspergillus terreus SUK-1 was grown on PKC in (SSF) using column bioreactor. The optimum condition were achieved after two washes of fermented PKC by adding of 10% glycerol (v/v) soaked for 10 h at the room temperature with solvent to ratio, 1:5 (w/v).

Bio-processing of agro-byproducts to animal feed

Agricultural and food-industry residues constitute a major proportion (almost 30%) of worldwide agricultural production. These wastes mainly comprise lignocellulosic materials, fruit and vegetable wastes, sugar-industry wastes as well as animal and fisheries refuse and byproducts. Agro-residues are rich in many bioactive and nutraceutical compounds, such as polyphenolics, carotenoids and dietary fiber among others. Agro residues are a major valuable biomass and present potential solutions to problems of animal nutrition and the worldwide supply of protein and calories, if appropriate technologies can be used for their valorization by nutrient enrichment. Technologies available for protein enrichment of these wastes include solid substrate fermentation, ensiling, and high solid or slurry processes. Technologies to be developed for the reprocessing of these wastes need to take account of the peculiarities of individual wastes and the environment in which they are generated, reprocessed, and used. In particular, such technologies need to deliver products that are safe, not just for animal feed use, but also from the perspective of human feeding. This review focuses on the major current applications of solid-state fermentation in relation to the feed sector.

Involvement of Physical Parameters in Medium Improvement for Tannase Production by Aspergillus niger FETL FT3 in Submerged Fermentation

Aspergillus niger FETL FT3, a local extracellular tannase producer strain that was isolated from one of dumping sites of tannin-rich barks of Rhizophora apiculata in Perak, Malaysia. This fungus was cultivated in 250 mL Erlenmeyer flask under submerged fermentation system. Various physical parameters were studied in order to maximize the tannase production. Maximal yield of tannase production, that is, 2.81 U per mL was obtained on the fourth day of cultivation when the submerged fermentation was carried out using liquid Czapek-Dox medium containing (percent; weight per volume) 0.25% NaNO₃, 0.1% KH₂PO₄, 0.05% MgSO₄ ·7H₂O, 0.05% KCl, and 1.0% tannic acid. The physical parameters used initial medium pH of 6.0, incubation temperature of 30°C, agitation speed of 200 rpm and inoculums size of 6 × 10⁶ spores/ ml. This research has showed that physical parameters were influenced the tannase production by the fungus with 156.4 percent increment.

Optimization of temperature, moisture content and inoculum size in solid state fermentation to enhance mannanase production by Aspergillus terreus SUK-1 using RSM

Optimization of three parameters, temperature (25-35 degrees C), moisture content (40% (w/v)-60% (w/v) and inoculum sizes (5% (w/v)-15% (w/v) were investigated and optimized by Response Surface Methodology (RSM) for optimal mannanase production by Aspergillus terreus SUK-1. A second order polynomial equation was fitted and the optimum condition was established. The result showed that the moisture content was a critical factor in terms of its effect on mannanase. The optimum condition for mannanase production was predicted at 42.86% (w/v) initial moisture (31 C) temperature and 5.5% (w/v) inoculum size. The predicted optimal parameter were tested in the laboratory and the mannanase activity 45.12 IU mL-1 were recorded to be closed to the predicted value (44.80 IU mL-1). Under the optimized SSF condition (31 degrees C, 42.86% moisture content (w/v) and 5.5% inoculum size (w/v)), the maximum mannanase production was to prevail about 45.12 IU mL-1 compare to before optimized (30 degrees C, 50% moisture content (w/v) and 10% inoculum size (w/v)) was only 34.42 IU mL-1.