Supporting Information for a Review on Development and Application of Plant-Based Bio-Flocculants and Grafted

Supporting Information for

A review on development and application of plant-based bio-flocculants and grafted bio- flocculants

Chai Siah Leea,b, Mei Fong Chonga*, John Robinsonb, Eleanor Binnerb aDepartment of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham Malaysia Campus, 43500 Semenyih, Selangor, Malaysia bDepartment of Chemical and Environmental Engineering, University of Nottingham, Nottingham NG7 2RD, UK

* Corresponding author. Tel.: +60 3 8924 8347; fax: +60 3 8924 8017. E-mail addresses: [email protected] (M.F. Chong), [email protected] (C.S. Lee), [email protected] (J. Robinson), [email protected] (E. Binner)

Background of processing industries involving clarification/flocculation process

Beverage industry Clarifying or flocculating agents are widely needed in beverage production, especially vinegar and wine clarification, clarification of dates extract, sugar cane juice and fruit juices. By referring to Figure S1, clarification is a routine part in the wine manufacturing process, as well as in the vinegar production to reduce the turbidity, total solids in suspension and various iron compounds which are largely responsible for the clouding in wines and vinegars.1-3

Fresh fruits (e.g. grapes)

Destemming/crushing

Mash thermal treatment

Thermovinification

Juice extraction

Juice fermentation

Wine clarification/filtration

Wine stabilisation

Bottling and packaging

Figure S1. Process flow diagram of wine production

As shown in Figure S2, clarification by means of clarifying agents plays a vital role in the production of clear and high quality fruit juice. It is used to remove colloidally suspended particles and turbidity which are caused by proteins, polyphenols, pectins, and carbohydrates in the juices.4, 5 In addition, clarification and discoloration of dates extract is one of the most important steps to free the extracted raw juice from non-soluble matter, soluble (e.g. colouring matter) and semi-soluble (e.g. pectin) materials in production of several products such as syrup, jam, date-jelly, date butter, vinegar and wine.6, 7 In the processing of sugar from sugar cane juice, clarification is essential to remove the organic and inorganic constituents in soluble, suspended and colloidal form and minimise colour formation.8

Fresh fruits

Washing and sorting

Screw press

Heating

Clarification and filtration

Evaporation

Concentrated fruit juice Figure S2. Process flow diagram of fruit juice production

As reported in Table 3, clarifying agents such as activated carbon, gelatin, albumen, bentonite and etc. are commonly used as clarification agents in beverage processing. However, they have generally been found unsatisfactory in terms of the cost involved, trouble of treatment, and lack of permanency in the results attained.1 Inadequate or improper use of these materials generally results in a reclouding of the clarified product.3 Chitosan has been investigated as an alternative option in fruit juice clarification.9-11 However, its use is hindered and shows limited potential for industrial acceptance because of seasonal and limited supply, inconsistent physical chemical properties and environmental problems.12, 13 In sugar industry, the use of lime and synthetic polymers as clarifying agents is not recommended nowadays due to the hidden toxicity effect to human health. In addition, the use of lime, chemical polymers, activated carbon and bentonite will generate solid waste which is difficult to dispose. Plant-based bio-flocculants are suggested to be used as clarifying agent in aiding the separation of suspended particles and turbidity from beverage, fruit juice or fruit extracts. Further, it is non-toxic and biodegradable, derived and extracted from natural sources, easily dissolved in water at room temperature; the treated effluent and the sludge have no negative environmental impact. Thus, it may be used as an alternative agent to the current clarifying agents for refining of fruit juices and fruit extracts.

Food industry Flocculation process could be used in seafood or meat processing industry to recover the muscle proteins from the by-products (meat left over on bones, head, skin, etc.). Processing of the by- products would enable the food processing industry to diversify its product offerings and offer another source of highly nutritious proteins for human consumption beside minimising environmental stresses due to their processing waste.14 As shown in Table 3, isoelectric solubilisation or precipitation has been applied to remove the impurities such as bones, scales, skin, etc., from by-products and resulting in protein recovery yields.14, 15 However, the last step

S3 of this method which is dewatering of the precipitated protein is inefficient and requires a high gravity force and extended time. Therefore, scale up to pilot plant is limited by this disadvantage because industrial settings require short centrifugation time in order to maintain economic feasibility.15 A study has been conducted to determine the separation efficiency of fish proteins recovered from fish processing by-products by means of isoelectric solubilisation/precipitation enhanced with a wide range of polymeric flocculants (anionic, non-ionic and cationic).15 The results proved that this method could potentially be used to recover muscle proteins from the by- products. However, the safety of proteins recovered from fish with the aid of the synthetic flocculants on human and animal health has limited its usage. In this respect, the use of plant- based bio-flocculants that exhibit the similar flocculating property as polymeric flocculants is proposed to aid in dewatering of the precipitated protein after isoelectric solubilisation treatment. The dewatering efficiency can be enhanced, hence reduce the energy consumption and centrifugation time. Additionally, the safety concern of the products recovered using bio- flocculants is eliminated.

Mineral industry Natural occurring kaolin clays vary considerably in their colour properties. As shown in Figure S3, selective flocculation is one of the widely used techniques to remove the discolouring contaminants (e.g. titanium and iron minerals, and impurity clay minerals), thereby improving the brightness and making the kaolin acceptable for pigment, coatings, cosmetic and pharmaceutical applications. 16-19

Crude kaolin clay

Formation of aqueous kaolin suspension or slurry

Fractionation to remove the coarser fraction

Selective flocculation

Bleaching

Dewatering

Rinsing of the filter cake

Drying Figure S3. Process flow diagram of kaolin clay production20

Anionic flocculants such as polymers of sodium acrylate, acrylamide and also sulphonate polymers are widely used for flocculating mineral suspensions.21, 22 Nuntiya et al.23 has studied the application of electrolytes (NaCl and CaCl2), low molecular weight polymer (polyvinyl

S4 alcohol, PVA) and high molecular weight polyacrylamide (PAM) on kaolin flocculation process. It was found that the floc size and floc strength increased with increasing cation valency in the electrolytes and increasing molecular weight in the polymers. However, conventional flocculants have the problems of non-biodegradable and dispersion of monomers or residual polymers in the kaolin slurry that may represent a health hazard.24-26 In addition, contamination of the clay product by the presence of the flocculating agent, may require additional processes to remove the flocculant and is significantly deleterious to the product theology.19 The flocculating ability of plant-based bio-flocculants in synthetic wastewater (kaolin suspension) has been verified.27 Therefore, it can be used to replace polymers as selective flocculants to flocculate the kaolin and leave the discolouring contaminants in the supernatant due to its advantages of green and biodegradable characteristics. The flocculated kaolin has no chemical contamination and is safe to be applied in production of consumer products.

Papermaking industry Flocculating agent systems are generally and extensively used to improve the retention of fibre fines and fillers in papermaking process,28, 29 as shown in Figure S4. It promotes the flocculation by aggregating the fine particles and fibres to form flocs that are large enough to be retained within the finer network or could be attached to fiber surfaces by attractive forces.30, 31 Generally, the flocculating agents/retention aids are often polyelectrolytes whose mechanisms of operation depend on the molecular weight and charge density.32, 33

Pulp materials

Preparation of aqueous slurry of pulp or wood cellulosic fibers (stock)

Dilution (“thin”) of the stock

Addition of filler and sizing materials (e.g. clay and titanium oxide)

Addition of cationic polymers

Addition of retention aid (e.g. anionic polymer)

Wet end system with papermaking machine (water removal, beating and refining)

Formation of paper product

Pressing and drying

Dry paper roll/sheet

Figure S4. Process flow diagram of papermaking process34

The application of bio-flocculants in papermaking retention is gaining much more attention lately. Bio-flocculants such as modified starch, modified celluloses and chitosan have been studied as papermaking retention and dewatering aids because it has the ability to bind coating fillers and pigments as well as to retain the cellulose fibres.28, 31, 35 However, starch modification has the challenge to produce starch modified products that are safe to the consumer and kind to the environment.36 There are debates regarding the chemical methods and the harsh conditions used in the modification process. Besides, its production is considered a competition to the primary energy source of humans because starches are mainly derived from potatoes, wheat and rice.37 On the other hand, application of chitosan in papermaking retention was proven to be comparable to synthetic flocculants but the flocs formed were smaller and weaker.28 Stricter governmental requirements for controlling the contaminants from papermaking effluents and the chemicals used in the synthesis of modified starches has led the paper industry to search for bio-flocculants as retention aids. Plant-based bio-flocculants provide an alternative to replace the polyelectrolytes and modified starches in retention of fibres and fillers and sludge dewatering. Bio-flocculants are readily dissolved in water; its preparation is simple and easy, no safety concerns related to its handling and can even be added directly to the papermaking process which is contracted to the complexity synthesis and preparation process of modified starches.38 Additionally, the treated effluent is non-toxic and ready for disposal. Some studies have proven that bio-flocculants are workable in direct flocculation process,39, 40 thus its usage may eliminate the addition of cationic and anionic polymers in papermaking process.

Oleo-chemical and biodiesel industries In industrial practice, glycerol-rich solution (sweetwater) or crude glycerol produces from oleo- chemical and biodiesel plants contains glycerol as the major component, methanol, water, inorganic salt (catalyst residue), free fatty acids, methyl esters, lipids, unreacted (vegetable oil) mono-, di- and triglycerides and a variety of other non-glycerol organic matter in varying amount.41, 42 It can be further purified into pure glycerol which then can be used as glycerol feed in other production processes.43 Chemical treatment is generally conducted in batches as a pre-treatment process to purify crude glycerol.44 The overall chemical treatment process is illustrated in Figure S5. First, a cooling and settling step is used to separate the soaps and fatty acids. The fatty acids are less soluble at lower temperatures and rise to the surface, where they can be removed by skimming. Second, the skimmed and settled glycerol is transferred to the first treatment tank. Third, a coagulant may be added to cause the residual fatty acids to form insoluble soaps, which coagulate followed by pH adjustment. Finally, the filtrate from the first press flows to the second treatment tank. The primary purified glycerol is then sent to the evaporators for concentration before further purified through distillation process.43 However, chemical treatment has the disadvantages of high chemical consumption and production of toxic and unsafe effluent.43, 45

Figure S5. Chemical treatment process of soap lyes (sweetwater)44

Membrane technology such as micro and ultra-filtration using membranes has been introduced lately to replace conventional purification methods but fouling phenomenon is the major problems in membrane operations which can cause significant flux decline by several different types of hindrance (e.g. adsorption, pore blockage and solute aggregation on the membrane surface).46, 47 Bio-flocculants can be used as a pre-treatment option to replace chemical treatment in first treatment tank and membrane filtration in removal of unreacted oil or fat, unreacted catalyst and other impurities from crude glycerol. The capability of bio-flocculants to remove organic contaminants from wastewater has been examined48, 49 without the requirement of pH alteration during bio-flocculation process. This method does not require chemical addition, lower cost, environmental friendly nature and ease of operation.

References (1) Saywell, L. G. Wine and vinegar clarification process. U.S. Patent US2043713 A, Jun 9, 1936. (2) López, F.; Pescador, P.; Güell, C.; Morales, M. L.; García-Parrilla, M. C.; Troncoso, A. M., Industrial vinegar clarification by cross-flow microfiltration: effect on colour and polyphenol content. Journal of Food Engineering 2005, 68, (1), 133-136. (3) Saywell, L. G., Clarification of Wine. Industrial & Engineering Chemistry 1934, 26, (9), 981-982. (4) Turfan, Ö.; Türkyılmaz, M.; Yemiş, O.; Özkan, M., Anthocyanin and colour changes during processing of pomegranate (Punica granatum L., cv. Hicaznar) juice from sacs and whole fruit. Food Chemistry 2011, 129, (4), 1644-1651. (5) Lee, W. C.; Yusof, S.; Hamid, N. S. A.; Baharin, B. S., Effects of fining treatment and storage temperature on the quality of clarified banana juice. LWT - Food Science and Technology 2007, 40, (10), 1755-1764. (6) Gamal A. El-Sharnouby, S. M. A.-E. a. M. M. A. O., Utilization of enzymes in the production of liquid sugar from dates. African Journal of Biochemistry Research 2009, 3, (3), 41-47. (7) Al-Farsi, M. A., Clarification of date juice. International Journal of Food Science & Technology 2003, 38, (3), 241-245. (8) Fabio Alessio Romano Dionisi, R. J. C. Sugar cane juice clarification process. U.S. Patent US 20090126720 A1, May 21, 2009. (9) Domingues, R. C. C.; Faria Junior, S. B.; Silva, R. B.; Cardoso, V. L.; Reis, M. H. M., Clarification of passion fruit juice with chitosan: Effects of coagulation process variables and comparison with centrifugation and enzymatic treatments. Process Biochemistry 2012, 47, (3), 467-471. (10) Chatterjee, S.; Chatterjee, S.; Chatterjee, B. P.; Guha, A. K., Clarification of fruit juice with chitosan. Process Biochemistry 2004, 39, (12), 2229-2232. (11) Martín-Diana, A. B.; Rico, D.; Barat, J. M.; Barry-Ryan, C., Orange juices enriched with chitosan: Optimisation for extending the shelf-life. Innovative Food Science & Emerging Technologies 2009, 10, (4), 590- 600.

(12) Rungsardthong, V.; Wongvuttanakul, N.; Kongpien, N.; Chotiwaranon, P., Application of fungal chitosan for clarification of apple juice. Process Biochemistry 2006, 41, (3), 589-593. (13) Chatterjee, S.; Adhya, M.; Guha, A. K.; Chatterjee, B. P., Chitosan from Mucor rouxii: production and physico-chemical characterization. Process Biochemistry 2005, 40, (1), 395-400. (14) Chen, Y.-C.; Jaczynski, J., Protein Recovery from Rainbow Trout (Oncorhynchus mykiss) Processing Byproducts via Isoelectric Solubilization/Precipitation and Its Gelation Properties As Affected by Functional Additives. Journal of Agricultural and Food Chemistry 2007, 55, (22), 9079-9088. (15) Taskaya, L.; Jaczynski, J., Flocculation-enhanced protein recovery from fish processing by-products by isoelectric solubilization/precipitation. LWT - Food Science and Technology 2009, 42, (2), 570-575. (16) Weir, S. Flocculation of mineral suspensions. Google Patent WO 2002044093 A2, Jun 6, 2002. (17) López-Galindo, A.; Viseras, C.; Cerezo, P., Compositional, technical and safety specifications of clays to be used as pharmaceutical and cosmetic products. Applied Clay Science 2007, 36, (1–3), 51-63. (18) Jun Yuan, B. E. E., Windell R. Andrews Method for beneficiating discolored kaolin to produce high brightness coating clay. U.S. Patent US 5685900 A, Nov 11, 1997. (19) Joseph C S Shi, C. L. W., Robert A Lowe, Cesar I Basilio Beneficiation with selective flocculation using hydroxamates. Google Patent WO 1999047266 A1, Sept 23, 1999. (20) Bomi M. Bilimoria, W. E. T. Process for producing a kaolin clay product. U.S. Patent US 5223463 A, Jun 29, 1993. (21) Halverson, F. Process for the flocculation of suspended solids. U.S. Patent US 4342653 A, Aug 3, 1982. (22) Lawrence J. Connelly, P. F. R., Dodd W. Fong, Ralph W. Kaesler Sulphonate-containing terpolymers as flocculants for suspended solids. Grant Patent CA 1285450 C, Jul 2, 1991. (23) Nuntiya, N. C. a. A., Influence of pH, Electrolytes and Polymers on Flocculation of Kaolin Particle. Chiang Mai J. Sci. 2008, 35, (1), 11-16. (24) Renault, F.; Sancey, B.; Badot, P. M.; Crini, G., Chitosan for coagulation/flocculation processes – An eco- friendly approach. European Polymer Journal 2009, 45, (5), 1337-1348. (25) Young-Han Bae, H.-J. K., Eun-Joo Lee, Nak-Chang Sung, Sung-Sik Lee, and Young-Han Kim, Potable water treatment by polyacrylamide base flocculants, coupled with an inorganic coagulant. Environmental Engineering Research 2007, 12, (1), 21-29. (26) Bolto, B.; Gregory, J., Organic polyelectrolytes in water treatment. Water Research 2007, 41, (11), 2301- 2324. (27) Anastasakis, K.; Kalderis, D.; Diamadopoulos, E., Flocculation behavior of mallow and okra mucilage in treating wastewater. Desalination 2009, 249, (2), 786-791. (28) Raluca Nicu, E. B., Ruben Miranda, Angeles Blanco, Flocculation Efficiency of Chitosan for Papermaking Applications. BioResources 2013, 8, (1), 768-784. (29) Rasteiro, M. G.; Garcia, F. A. P.; del Mar Pérez, M., Applying LDS to Monitor Flocculation in Papermaking. Particulate Science and Technology 2007, 25, (3), 303-308. (30) Zakrajšek, N.; Fuente, E.; Blanco, A.; Golob, J., Influence of Cationic Starch Adsorption on Fiber Flocculation. Chemical Engineering & Technology 2009, 32, (8), 1259-1265. (31) Lauri Kuutti, S. H., Sari Hyvarinen, Hannu Mikkonen, Riikka Koski, Soili Peltonen, Tapani Suortti, Hanna Kyllönen, PROPERTIES AND FLOCCULATION EFFICIENCY OF CATIONIZED BIOPOLYMERS AND THEIR APPLICABILITY IN PAPERMAKING AND IN CONDITIONING OF PULP AND PAPER SLUDGE. BioResources 2011, 6, (3), 2836-2850. (32) Jaroslav Melzer, H.-U. S. Retention aids and flocculants based on polyacrylamides. Grant Patent CA 1050680 A1, Mar 13, 1979. (33) Cadotte, M.; Tellier, M.-E.; Blanco, A.; Fuente, E.; van de Ven, T. G. M.; Paris, J., Flocculation, Retention and Drainage in Papermaking: A Comparative Study of Polymeric Additives. The Canadian Journal of Chemical Engineering 2007, 85, (2), 240-248. (34) Thomas E. Taggert, J., Fla; Jeffrey S. Noe, Newark; Allan M. Springer Papermaking process. U.S. Patent. 4,752,356, 1988. (35) Bratskaya, S.; Schwarz, S.; Liebert, T.; Heinze, T., Starch derivatives of high degree of functionalization: 10. Flocculation of kaolin dispersions. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2005, 254, (1–3), 75-80. (36) Kaur, B.; Ariffin, F.; Bhat, R.; Karim, A. A., Progress in starch modification in the last decade. Food Hydrocolloids 2012, 26, (2), 398-404. (37) Bemiller, J. N., Starch Modification: Challenges and Prospects. Starch - Stärke 1997, 49, (4), 127-131.

(38) Michele M. Merrette, J. J. T., Paul H. Richardson STARCHES FOR USE IN PAPERMAKING. U.S. Patent US 6,843,888 B2, Jan 18, 2005. (39) Mishra, A.; Bajpai, M., Flocculation behaviour of model textile wastewater treated with a food grade polysaccharide. Journal of Hazardous Materials 2005, 118, (1–3), 213-217. (40) Mishra, A.; Yadav, A.; Agarwal, M.; Bajpai, M., Fenugreek mucilage for solid removal from tannery effluent. Reactive and Functional Polymers 2004, 59, (1), 99-104. (41) Singhabhandhu, A.; Tezuka, T., A perspective on incorporation of glycerin purification process in biodiesel plants using waste cooking oil as feedstock. Energy 2010, 35, (6), 2493-2504. (42) Sdrula, N., A study using classical or membrane separation in the biodiesel process. Desalination 2010, 250, (3), 1070-1072. (43) Mah, S.-K.; Leo, C. P.; Wu, T. Y.; Chai, S.-P., A feasibility investigation on ultrafiltration of palm oil and oleic acid removal from glycerin solutions: Flux decline, fouling pattern, rejection and membrane characterizations. Journal of Membrane Science 2012, 389, (0), 245-256. (44) Shahidi, F., Bailey's Industrial Oil and Fat Products. In Industrial and Nonedible Products from Oils and Fats, 6th ed.; Wiley-Interscience: 2005; Vol. 6, p 519. (45) Wagner Celio Ferraz Lourenco, R. M., Jose Eduardo Cielo Process for the purification of crude glycerol. European Patent EP 2295394 A1, Mar 16, 2011. (46) Wu, T. Y.; Mohammad, A. W.; Md. Jahim, J.; Anuar, N., Palm oil mill effluent (POME) treatment and bioresources recovery using ultrafiltration membrane: Effect of pressure on membrane fouling. Biochemical Engineering Journal 2007, 35, (3), 309-317. (47) Aldo, B. T. O. J. C. G. P. R. Process for purifying crude glycerol. European Patent EP 0 358 255 A1, Mar 14, 1990. (48) Al-Hamadani, Y. A. J.; Yusoff, M. S.; Umar, M.; Bashir, M. J. K.; Adlan, M. N., Application of psyllium husk as coagulant and coagulant aid in semi-aerobic landfill leachate treatment. Journal of Hazardous Materials 2011, 190, (1–3), 582-587. (49) Srinivasan, R.; Mishra, A., OKRA (HIBISCUS ESCULENTUS) AND FENUGREEK (TRIGONELLA FOENUM GRACEUM) MUCILAGE: CHARACTERIZATION AND APPLICATION AS FLOCCULANTS FOR TEXTILE EFFLUENT TREATMENTS. Chinese Journal of Polymer Science 2008, 26, (06), 679-687.