A Short Review on Valorization of Slaughterhouse Wastes for Biodiesel Production

Study of Processing Conditions during Enzymatic Hydrolysis of Deer By-Product Tallow for Targeted Changes at the Molecular Level and Properties of Modified Fats

In most cases, the unused by-products of venison, including deer tallow, are disposed of in rendering plants. Deer tallow contains essential fatty acids and can be used to prepare products for everyday food and advanced applications. This work aimed to process deer tallow into hydrolyzed products using microbial lipases. A Taguchi design with three process factors at three levels was used to optimize the processing: amount of water (8, 16, 24%), amount of enzyme (2, 4, 6%), and reaction time (2, 4, 6 h). The conversion of the tallow to hydrolyzed products was expressed by the degree of hydrolysis. The oxidative stability of the prepared products was determined by the peroxide value and the free fatty acids by the acid value; further, color change, textural properties (hardness, spreadability, stickiness, and adhesiveness), and changes at the molecular level were observed by Fourier transform infrared spectroscopy (FTIR). The degree of hydrolysis was 11.8-49.6%; the peroxide value ranged from 12.3 to 29.5 µval/g, and the color change of the samples expressed by the change in the total color difference (∆E*) was 1.9-13.5. The conditions of enzymatic hydrolysis strongly influenced the textural properties: hardness 25-50 N, spreadability 20-40 N/s, and stickiness < 0.06 N. FTIR showed that there are changes at the molecular level manifested by a decrease in ester bonds. Enzymatically hydrolyzed deer tallow is suitable for preparing cosmetics and pharmaceutical matrices.

A critical review on slaughterhouse waste management and framing sustainable practices in managing slaughterhouse waste in India

Global meat consumption is on a rise with around 253 million metric tons of meat produced globally in the year 2020. Because of the rise in population and change in food preferences, meat consumption trend is likely to continue. Meat production by animal slaughtering increases the slaughterhouse wastes in the form of both solid and liquid wastes. Although various technologies for slaughterhouse waste management are available in developed countries, the effective utilization of slaughterhouse waste management is still missing in developing countries like India. India plays an active role in the meat export business globally and stood 2nd in the world with a total export valuation of 2.89 billion US $ in the year 2020. In this context, this study presents a critical overview of the current technological advancements in the global slaughterhouse waste management including utilization of by-products and further, the prevailing slaughterhouse waste management of India is discussed. Finally, a sustainable slaughterhouse waste management strategy emphasizing circular economy and regulations improvements have been suggested for India to compete in this sector at global scale.

Enhancing the Catalytic Activity of Eggshell-Derived CaO Catalyst and Its Application in Biodiesel Production from Waste Chicken Fat

The comparatively greater cost of producing biodiesel in comparison to petroleum diesel is one of the key drawbacks. Eggshells and leftover chicken fat are examples of poultry wastes that can be used to produce biodiesel at a low cost as catalysts and oil, respectively. In this study, eggshell-derived CaO and its doping with sodium methoxide catalyst for enhancing catalytic activity was synthesized for the transesterification of waste chicken fat and characterized by FT-IR and XRD analyses. XRD studies confirmed the crystalline structure of the developed catalyst and doping of sodium with eggshell-derived CaO. The transesterification reaction was performed at different reaction parameters such as the catalyst loading, the methanol to oil ratio, the reaction temperature, and the reaction time. The biodiesel produced at the maximum yield was evaluated by gas chromatography mass spectrometry analysis. A maximum yield of 96% biodiesel was obtained with catalyst loading of 2 wt% of oil, as well as a methanol to oil ratio of 13:1 at 60 °C in 1 h. The output demonstrates that eggshell waste is a potentially accessible source of biomass-derived nano catalyst for the synthesis of biodiesel using chicken fat as a feedstock.

Submerged Fermentation of Animal Fat By-Products by Oleaginous Filamentous Fungi for the Production of Unsaturated Single Cell Oil

Animal waste fats were explored as a fermentation substrate for the production of high-value unsaturated single cell oil (SCO) using oleaginous fungi, Mucor circinelloides and Mortierella alpina. Both strains showed good growth and lipid accumulation when using animal fat as a single carbon source. The biomass concentration of 16.7 ± 2.2 gDCW/L and lipid content of 54.1%wt (of dry cell weight) were obtained for Mucor circinelloides in shake flask experiments, surpassing the biomass yield achieved in batch and fed-batch fermentation. In contrast, Mortierella alpina gave the highest biomass concentration (8.3 ± 0.3 gDCW/L) and lipid content (55.8%wt) in fed-batch fermentation. Fat grown Mortierella alpina was able to produce arachidonic acid (ARA), and the highest ARA content of 23.8%wt (of total lipid weight) was in fed-batch fermentation. Gamma-linolenic acid (GLA) was produced by both fungal strains. At the end of fed-batch fermentation, the GLA yields obtained for Mucor circinelloides and Mortierella alpina were 4.51%wt and 2.77%wt (of total lipid weight), respectively. This study demonstrates the production of unsaturated SCO-rich fungal biomass from animal fat by fermentation.

Inactivation of indicator microorganisms and biological hazards by standard and/or alternative processing methods in Category 2 and 3 animal by-products and derived products to be used as organic fertilisers and/or soil improvers

The European Commission requested EFSA to assess if different thermal processes achieve a 5 log10 reduction in Enterococcus faecalis or Salmonella Senftenberg (775W) and (if relevant) a 3 log10 reduction in thermoresistant viruses (e.g. Parvovirus) as well as if different chemical processes achieve a 3 log10 reduction of eggs of Ascaris sp., in eight groups of Category 2 and 3 derived products and animal by-products (ABP). These included (1) ash derived from incineration, co-incineration and combustion; (2) glycerine derived from the production of biodiesel and renewable fuels; (3) other materials derived from the production of biodiesel and renewable fuels; (4) hides and skins; (5) wool and hair; (6) feathers and down; (7) pig bristles; and (8) horns, horn products, hooves and hoof products. Data on the presence of viral hazards and on thermal and chemical inactivation of the targeted indicator microorganisms and biological hazards under relevant processing conditions were extracted via extensive literature searches. The evidence was assessed via expert knowledge elicitation. The certainty that the required log10 reductions in the most resistant indicator microorganisms or biological hazards will be achieved for each of the eight groups of materials mentioned above by the thermal and/or chemical processes was (1) 99-100% for the two processes assessed; (2) 98-100% in Category 2 ABP, at least 90-99% in Category 3 ABP; (3) 90-99% in Category 2 ABP; at least 66-90% in Category 3 ABP; (4) 10-66% and 33-66%; (5) 1-33% and 10-50%; (6) 66-90%; (7) 33-66% and 50-95%; (8) 66-95%, respectively. Data generation on the occurrence and reduction of biological hazards by thermal and/or chemical methods in these materials and on the characterisation of the usage pathways of ABP as organic fertilisers/soil improvers is recommended.

Efficient production of polyhydroxybutyrate from slaughterhouse waste using a recombinant strain of Cupriavidus necator DSM 545

Slaughterhouse residues are greatly available and can pose a threat to the environment if not disposed of correctly. Such by-products can be proficiently processed into polyhydroxyalkanoates by accurately selected and developed bacterial strains. Cupriavidus necator DSM 545, one of the most efficient polyhydroxyalkanoates-producing strain, cannot grow well on fatty substrates. In this work, a recombinant lipolytic C. necator microbe was developed for the efficient conversion of slaughtering by-products into polyhydroxyalkanoates. Two lipase sequences, lipC and lipH of Pseudomonas stutzeri BT3, were effectively expressed in C. necator DSM 545. The engineered strain C. necator DSM 545 JR11, selected for the outstanding extracellular lipolytic activity, produced high levels of polyhydroxyalkanoates (nearly 65% of cell dry mass) from udder, jowl and membrane caul fat. This research is crucial to the cost-effective one-step processing of slaughterhouse waste into polyhydroxyalkanoates with useful applications in several industrial and medical sectors.

Environmentally benign solid catalysts for sustainable biodiesel production: A critical review

Versatile bio-derived catalysts have been under dynamic investigation as potential substitutes to conventional chemical catalysts for sustainable biodiesel production. This is because of their unique, low-cost benefits and production processes that are environmentally and economically acceptable. This critical review aspires to present a viable approach to the synthesis of environmentally benign and cost-effective heterogeneous solid-base catalysts from a wide range of biological and industrial waste materials for sustainable biodiesel production. Most of these waste materials include an abundance of metallic minerals like potassium and calcium. The different approaches proposed by researchers to derive highly active catalysts from large-scale waste materials of a re-usable nature are described briefly. Finally, this report extends to present an overview of techno-economic feasibility of biodiesel production, its environmental impacts, commercial aspects of community-based biodiesel production and potential for large-scale expansion.

Developments in the Use of Lipase Transesterification for Biodiesel Production from Animal Fat Waste

Biodiesel constitutes an attractive source of energy because it is renewable, biodegradable, and non-polluting. Up to 20% biodiesel can be blended with fossil diesel and is being produced and used in many countries. Animal fat waste represents nearly 6% of total feedstock used to produce biodiesel through alkaline catalysis transesterification after its pretreatment. Lipase transesterification has some advantages such as the need of mild conditions, absence of pretreatment, no soap formation, simple downstream purification process and generation of high quality biodiesel. A few companies are using liquid lipase formulations and, in some cases, immobilized lipases for industrial biodiesel production, but the efficiency of the process can be further improved. Recent developments on immobilization support materials such as nanoparticles and magnetic nanomaterials have demonstrated high efficiency and potential for industrial applications. This manuscript reviews the latest advances on lipase transesterification and key operational variables for an efficient biodiesel production from animal fat waste.

Trends in Biodiesel Production from Animal Fat Waste

The agro-food industry generates large amounts of waste that contribute to environmental contamination. Animal fat waste constitutes some of the most relevant waste and the treatment of such waste is quite costly because environmental regulations are quite strict. Part of such costs might be reduced through the generation of bioenergy. Biodiesel constitutes a valid renewable source of energy because it is biodegradable, non-toxic and has a good combustion emission profile and can be blended up to 20% with fossil diesel for its use in many countries. Furthermore, up to 70% of the total cost of biodiesel majorly depends on the cost of the raw materials used, which can be reduced using animal fat waste because they are cheaper than vegetable oil waste. In fact, 6% of total feedstock corresponded to animal fat in 2019. Transesterification with alkaline catalysis is still preferred at industrial plants producing biodiesel. Recent developments in heterogeneous catalysts that can be easily recovered, regenerated and reused, as well as immobilized lipases with increased stability and resistance to alcohol denaturation, are promising for future industrial use. This manuscript reviews the available processes and recent advances for biodiesel generation from animal fat waste.