STATISTICAL OPTIMIZATION OF A NOVEL LOW-COST MEDIUM BASED ON REGIONAL AGRO-INDUSTRIAL BY-PRODUCTS FOR THE PRODUCTION OF PROTEOLYTIC ENZYMES BY Bacillus cereus

Bacillus sp. are specific producers of peptidase amongst bacteria and peptidase enzymes and are of significant ones due to their multifarious applications. Advances in industrial biotechnology offer potential opportunities for economic utilization of agro-industrial by-products for many biochemical reactions. Due to their rich organic nature, they can serve as an ideal substrate for the production of different value added products like peptidases. In the present work, an attempt was made to optimize different variables by Taguchi methodology for the production of peptidase using agro-industrial by-products hydrolyzed by a Bacillus cereus strain, resulting in brewer's spent grain (BSG) being the optimal organic substrate. Subsequently, operative variables for the BSG were investigated using Taguchi methodology in order to maximize the enzyme production. Additionally, the main medium components were optimized using a mixture design. Finally, the production of peptidase by B. cereus was investigated; also the possible interaction with other proteolytic microbial strains was evaluated. A notorious synergistic effect was observed when B. cereus was inoculated with Pseudomonas sp. These brought a triple benefit, first, opening the possibility to produce technical enzymes at low cost, second, giving greater value to a food industry by-product, and third, reducing the environmental impact caused by the product removal directly into the environment.     

STATISTICAL OPTIMIZATION OF A NOVEL LOW-COST MEDIUM BASED ON REGIONAL AGRO-INDUSTRIAL BY-PRODUCTS FOR THE PRODUCTION OF PROTEOLYTIC ENZYMES BY Bacillus cereus

Bacillus sp. are specific producers of peptidase amongst bacteria and peptidase enzymes and are of significant ones due to their multifarious applications. Advances in industrial biotechnology offer potential opportunities for economic utilization of agro-industrial by-products for many biochemical reactions. Due to their rich organic nature, they can serve as an ideal substrate for the production of different value added products like peptidases. In the present work, an attempt was made to optimize different variables by Taguchi methodology for the production of peptidase using agro-industrial by-products hydrolyzed by a Bacillus cereus strain, resulting in brewer's spent grain (BSG) being the optimal organic substrate. Subsequently, operative variables for the BSG were investigated using Taguchi methodology in order to maximize the enzyme production. Additionally, the main medium components were optimized using a mixture design. Finally, the production of peptidase by B. cereus was investigated; also the possible interaction with other proteolytic microbial strains was evaluated. A notorious synergistic effect was observed when B. cereus was inoculated with Pseudomonas sp. These brought a triple benefit, first, opening the possibility to produce technical enzymes at low cost, second, giving greater value to a food industry by-product, and third, reducing the environmental impact caused by the product removal directly into the environment.     

Challenges and opportunities of the bio-pesticides production by solid-state fermentation: filamentous fungi as a model

In recent years, production and use of bio-pesticides have increasing and replacing some synthetic chemical pesticides applied to food commodities. In this review, biological control is focused as an alternative, to some synthetic chemical treatments that cause environmental, human health, and food quality risks. In addition, several phytopathogenic microorganisms have developed resistance to some of these synthetic chemicals and become more difficult to control. Worldwide, the bio-pesticides market is growing annually at a rate of 44% in North America, 20% in Europe and Oceania, 10% in Latin and South American countries and 6% in Asia. Use of agro-industrial wastes and solid-state fermentation (SSF) technology offers an alternative to bio-pesticide production with advantages versus conventional submerged fermentations, as reduced cost and energy consumption, low production of residual water and high stability products. In this review, recent data about state of art regarding bio-pesticides production under SSF on agroindustrial wastes will be discussed. SSF can be defined as a microbial process that generally occurs on solid material in the absence of free water. This material has the ability to absorb water with or without soluble nutrients, since the substrate must have water to support the microorganism’s growth and metabolism. Changes in water content are analyzed in order to select the conditions for a future process, where water stress can be combined with the best spore production conditions, obtaining in this way an inexpensive biotechnological option for modern agriculture in developing countries.     

Production of feruloyl esterases and xylanases by Talaromyces stipitatus and Humicola grisea var. thermoidea on industrial food processing by-products

Feruloyl esterase (FAE) and xylanase activities were detected in culture supernatants from Humicola grisea var. thermoidea and Talaromyces stipitatus grown on brewers' spent grain (BSG) and wheat bran (WB), two agro-industrial by-products. Maximum activities were detected from cultures of H. grisea grown at 150 rpm, with 16.9 U/ml and 9.1 U/ml of xylanase activity on BSG and WB, respectively. Maximum FAE activity was 0.47 U/ml and 0.33 U/ml on BSG and WB, respectively. Analysis of residual cell wall material after microbial growth shows the preferential solubilisation of arabinoxylan and cellulose, two main polysaccharides present in BSG and WB. The production of low-cost cell-wall-deconstructing enzymes on agro-industrial by-products could lead to the production of low-cost enzymes for use in the valorisation of food processing wastes.     

Newly isolated microorganisms with potential application in biotechnology

Nowadays, food, cosmetic, environmental and pharmaceutical fields are searching for alternative processes to obtain their major products in a more sustainable way. This fact is related to the increasing demand from the consumer market for natural products to substitute synthetic additives. Industrial biotechnology appears as a promising area for this purpose; however, the success of its application is highly dependent of the availability of a suitable microorganism. To overcome this drawback, the isolation of microorganisms from diverse sources, including fermented food, adverse environments, contaminated samples or agro-industrial wastes is an important approach that can provide a more adaptable strain able to be used as biocatalyst and that exhibit resistance to industrial conditions and high yields/productivities in biotechnological production of natural compounds. The aim of this review is to provide a solid set of information on the state of the art of isolation and screening studies for obtaining novel biocatalysts able to produce natural compounds, focusing in aromas, biosurfactants, polysaccharides and microbial oils.     

Effect of synthetic and natural culture media on laccase production by white rot fungi

Laccase is among the major enzymes of white rot fungi involved in lignocellulose degradation. The present paper reports its production by two white rot fungi (Coriolus versicolor, Funalia trogii) under different nutritional conditions. Various synthetic culture media and natural culture medium (molasses wastewater) were tested. Enzyme production in various synthetic culture media, molasses wastewater (vinasse) culture medium and in the absence or presence of cotton stalk supplements showed that vinasse culture medium was a better laccase-inducer medium than the synthetic culture medium. Addition of cotton stalk to various media enhanced the enzyme production. The highest laccase activity was obtained in vinasse culture medium with cotton stalk.     

Production and potential biotechnological applications of microbial surfactants: An overview

Microbial surfactants are amphipathic molecules that consist of hydrophilic and hydrophobic domains, which allow partition of two fluid phases of varying degree of polarity. They are classified into two main groups: bioemulsifier and biosurfactant, depending on their molecular weight. Microbial surfactants occur in various categories according to their chemical nature and producing organisms. These biomolecules are produced by diverse groups of microorganisms including fungi, bacteria, and yeasts. Their production is significantly influenced by substrate type, fermentation technology and microbial strains. Owing to inherent multifunctional properties and assorted synthetic aptitude of the microbes, microbial surfactants are mostly preferred than their chemical counterparts for various industrial and biomedical applications including bioremediation, oil recovery; as supplements in laundry formulations and as emulsion-stabilizers in food and cosmetic industries as well as therapeutic agents in medicine. The present review discusses on production of microbial surfactants as promising and alternative broad-functional biomolecules for various biotechnological applications.     

Single cell oil production from a newly isolated <Emphasis Type="Italic">Candida viswanathii</Emphasis> Y-E4 and agro-industrial by-products valorization

Microbial lipids have drawn increasing attention in recent years as promising raw materials for biodiesel and added-value compounds production. To this end, new oleaginous yeast, Candida viswanathii Y-E4 was isolated, characterized and used for single cell oil (SCO) production. Physiologic and nutritional parameters optimization was carried out for improved biomass and lipid production. Y-E4 strain was able to use a wide range of substrates, especially C5 and C6 sugars as well as glycerol and hydrophobic substrates. The fatty acid profile analysis showed that oleic acid was the main component produced using different substrates. Batch and fed-bath fermentation were conducted using glucose as carbon source. Lipid production rate is twice higher in fed-batch culture providing a lipid content of 50 % (w/w). To minimize the SCO production cost, C. viswanathii Y-E4 was evaluated for its capacity to use different agro-industrial by-products for microbial oil production and changes in the fatty acid profile were monitored.     

Efficient production of ε-poly-<Emphasis Type="SmallCaps">l</Emphasis>-lysine from agro-industrial by-products by <Emphasis Type="Italic">Streptomyces</Emphasis> sp. M-Z18

ε-Poly-l-lysine (ε-PL)—a natural food preservative with wide antimicrobial activity and high food safety—is increasingly attracting widespread attention. However, the high cost of raw materials severely impairs its economy and utilization. In this study, agro-industrial by-products, i.e., fish meal coupled with corn steep liquor, were employed as alternative organic nitrogen sources for industrial ε-PL production by Streptomyces sp. M-Z18. An economical medium was then developed by using an artificial neural network. Amino acids analyses showed that the improved medium was rich in glutamate, arginine, lysine and aspartate, which not only elevated the acid tolerance capability of the mycelia but also enhanced cell growth and ε-PL production. Subsequently, a cost-effective and efficient strategy for ε-PL production was established on fermenter scale, based on the improved medium and two-stage pH control. Notably, ε-PL production and productivity reached 35.24 g/L and 4.85 g/L day in fed-batch fermentation. Further profit assessment at the 10 m³ scale indicated that application of this strategy resulted in a net profit increase of 9,057 USD. Therefore, the proposed strategy has great potential for industrial production of ε-PL.     

单萜类化合物的微生物合成

单萜类化合物是萜类化合物的一种,一般具有挥发性和较强的香气,部分单萜还具有抗氧化、抗菌、抗炎等生理活性,是医药、食品和化妆品工业的重要原料.近年来,利用微生物异源合成单萜类化合物的研究引起了科研人员的广泛关注,但因产量低、生产成本高等限制了其大规模应用.合成生物学的迅猛发展为微生物生产单萜类化合物提供了新的手段,通过改...     

Use of microbial cells of Corynebacterium diphtheriae for preparing a nutrient medium]

Nutrient media prepared on the basis of microbial cells (Corynebacteria diphtheriae) proved to be no less nutrient in comparison with conventional media prepared on the full-value food products. Use of diphtheria bacilli (by-products of diphtheria toxoid production) as the basis for nutrient media permitted to use up to 30% less food products for this purpose.     

Microbial food: microorganisms repurposed for our food

Sustainable food production is a key to solve complicated and intertwined issues of overpopulation, climate change, environment and sustainability. Microorganisms, which have been routinely consumed as a part of fermented foods and more recently as probiotic dietary supplements, can be repurposed for our food to present a sustainable solution to current food production system. This paper begins with three snapshots of our future life with microbial foods. Next, the importance, possible forms, and raw materials (i.e. microorganisms and their carbon and energy sources) of microbial foods are discussed. In addition, the production strategies, further applications and current limitations of microbial foods are discussed.     

Use of sugarcane bagasse and grass hydrolysates as carbon sources for xylanase production by Bacillus circulans D1 in submerged fermentation

The use of sugarcane bagasse and grass as low cost raw material for xylanase production by Bacillus circulans D1 in submerged fermentation was investigated. The microorganism was cultivated in a mineral medium containing hydrolysate of bagasse or grass as carbon source. High production of enzyme was obtained during growth in media with bagasse hydrolysates (8.4 U/mL) and in media with grass hydrolysates (7.5 U/mL). Xylanase production in media with hydrolysates was very close to that obtained in xylan containing media (7.0 U/mL) and this fact confirm the feasibility of using this agro-industrial byproducts by B. circulans D1 as an alternative to save costs on the enzyme production process.     

华根霉脂肪酶有机相合成酶活的研究

通过比较7种微生物脂肪酶的有机相合成酶活、水相水解酶活及在正庚烷中催化己酸乙酯合成的能力,证明了合成酶活与水解酶活相关性不高,合成酶活比水解酶活更能反映脂肪酶的合成能力。通过比较两株华根霉(Rhizopus chinensis)脂肪酶酶活,发现合成酶活相差较大,表明相同种属微生物的脂肪酶合成酶活存在不同。对．Rhizopus chinensis-2液态发酵产脂肪酶进程研究发现,水解酶活高峰先于合成酶活高峰大约12h。将不同培养时间的Rhizopus chinensis-2全细胞脂肪酶用于催化己酸乙酯合成,具有高合成酶活的全细胞脂肪酶催化己酸乙酯合成反应较快。因此,全细胞脂肪酶用于催化有机相酯合成反应时,具有高脂肪酶合成酶活的菌体具有较好的催化酯合成能力。     

Multifaceted roles of duckweed in aquatic phytoremediation and bioproducts synthesis

Duckweed (Lemnaceae) is a fast‐growing aquatic vascular plant. It has drawn an increasing attention worldwide due to its application in value‐added nutritional products and in sewage disposal. In particular, duckweed is a promising feedstock for bioenergy production. In this review, we summarized applications of duckweed from the following four aspects. Firstly, duckweed could utilize nitrogen, phosphorus, and inorganic nutrition in wastewater and reduces water eutrophication efficiently. During these processes, microorganisms play an important role in promoting duckweed growth and improving its tolerance to stresses. We also introduced our pilot‐scale test using duckweed for wastewater treatment and biomass production simultaneously. Secondly, its capability of fast accumulation of large amounts of starch makes duckweed a promising bioenergy feedstock, catering the currently increasing demand for bioethanol production. Pretreatment conditions prior to fermentation can be optimized to improve the conversion efficiency from starch to bioethanol. Furthermore, duckweed serves as an ideal source for food supply or animal feed because the composition of amino acids in duckweed is similar to that of whey protein, which is easily digested and assimilated by human and other animals. Finally, severing as a natural plant factory, duckweed has shown great potential in the production of pharmaceuticals and dietary supplements. With the surge of omics data and the development of Clustered Regularly Interspaced Short Palindromic Repeats technology, remodeling of the metabolic pathway in duckweed for synthetic biology study will be attainable in the future.     

Biotransformation and bioconversion of phenolic compounds obtainment: an overview

Phenolic compounds have recently been recognized for their influence on human metabolism, acting in the prevention of some chronic diseases as well as proving to be important antioxidants in food. Nevertheless, the extraction and concentration processes are usually carried out by organic solvent extraction from natural sources and can generate some drawbacks like phenolic compound degradation, lengthy process times and low yields. As a solution, some eco-friendly technologies, including solid-state fermentation (SSF) or enzymatic-assisted reaction, have been proposed as alternative processes. This article reviews the extraction of phenolic compounds from agro-industrial co-products by solid-state fermentation, even as friendly enzyme-assisted extractions. It also discusses the characteristics of each bioprocess system and the variables that affect product formation, as well as the range of substrates, microorganisms and enzymes that can be useful for the production of bioactive phenolic compounds.     

Enzymatic production of lactulose and 1-lactulose: current state and perspectives

Lactulose, a synthetic ketose disaccharide, has been widely used in food and pharmaceutical industries as prebiotic food additives and drugs against constipation and hepatic encephalopathy. Lactulose has, so far, been produced chemically using lactose on a commercial scale. The key problems associated with such chemical process are the cost of removal of the catalyst and colored by-products and the product safety. Enzymatic production of lactulose is safe, environment-friendly, and simpler in comparison to the chemical method. As a promising alternative to the chemical method, enzymatic conversion of lactose into lactulose by β-galactosidase or cellobiose 2-epimerase has recently gained a great deal of attention. This could be considered as a possible route for whey surplus because lactose is the major component of cheese whey. Herein, we summarize recent advances on the enzymatic synthesis of lactulose with emphasis on the selectivity of biocatalysts and their catalytic efficiency in free and immobilized forms. The production of 1-lactulose by enzymatic bioconversion of lactose has also been discussed. Furthermore, future research needs of β-galactosidase and cellobiose 2-epimerase for the enzymatic synthesis of lactulose and 1-lactulose are reviewed.     

Autohydrolysed <Emphasis Type="Italic">Tilapia nilotica</Emphasis> Fish Viscera as a Peptone Source in Bacteriocin Production

Fish processing generates large amounts of solid and liquid wastes. Many different by-products have been produced from fish processing wastes. Studies on solubilization of Bolti fish (Tilapia nilotica) viscera by endogenous enzymes at different pHs are described. Hydrolysis reactions were conducted with freshly thawed viscera utilizing an initial temperature gradient and terminated at various time points by heat inactivation of the enzymes. Various peptones obtained from hydrolysed visceral homogenates of Bolti fish residues showed their suitability for promoting the growth of lactic acid bacteria (mainly Lactobacillus sake Lb 706), microorganisms with particularly complex nutritional requirements especially peptidic sources. The assay of several treatments with L. sakei Lb 706, producer of the bacteriocin sakacin A, demonstrated that optimum conditions for biomass and bacteriocin production only imply a brief autohydrolysis at room temperature. The results showed that the Bolti fish hydrolysates gave remarkable results to those found in costly commercial media, specifically recommended for culturing and large-scale production of lactic acid bacteria.     

Oil cakes and their biotechnological applications--a review

Oil cakes have been in use for feed applications to poultry, fish and swine industry. Being rich in protein, some of these have also been considered ideal for food supplementation. However, with increasing emphasis on cost reduction of industrial processes and value addition to agro-industrial residues, oil cakes could be ideal source of proteinaceous nutrients and as support matrix for various biotechnological processes. Several oil cakes, in particular edible oil cakes offer potential benefits when utilized as substrate for bioprocesses. These have been utilized for fermentative production of enzymes, antibiotics, mushrooms, etc. Biotechnological applications of oil cakes also include their usages for vitamins and antioxidants production. This review discusses various applications of oil cakes in fermentation and biotechnological processes, their value addition by implementation in feed and energy source (for the production of biogas, bio-oil) as well.