Correction: Khoo et al. Liquid Biphasic System: A Recent Bioseparation Technology. Processes 2020, 8, 149

Error in References

In the original publication, there was an error after the proofreading process in which the sequence order of the references was adjusted ahead of another statement throughout the published article.; therefore, the authors wish to make the following corrections. With this correction, the Editorial Office together with the authors are making the following amendments to the published article [1]:

The following statement, “The application of the LBS has been applied for the extraction, separation, and purification of proteins, lipids, and carotenoids from microalgae [2,13]”. is replaced with the following references [2,13,14] as below in the published article.

The following statement, “It was started back in 1896 when Martinus Willem Beijerinck accidentally mixed an aqueous starch solution with gelatin and found that an immersible layer was formed between both the aqueous solutions [14,15]”. is replaced with the following references [15,16] as below in the published article.

The following statement, “This idea of LBS as an analytical separation technique was sparked by Per-Åke Albertsson in the 1960s who discovered the phenomenon by mixing two different polymers (e.g., polyethylene glycol and dextran) resulting in an aqueous medium containing two separable phases [14,16,17]”. is replaced with the following references [15,17,18] as below in the published article.

The following statement, “The LBS is well-known for the extraction of different biotechnological materials such as proteins, lipids, and carotenoids [1,18,19]”. is replaced with the following references [1,19,20] as below in the published article.

The following statement, “Likewise, LBS has the capability of directing the target biomolecules by partitioning them to the top phase for extraction [20]”. is replaced with the following references [21] as below in the published article.

The following statement, “Conventional polymer-based LBS which possess a low ionic system is generally used for the separation and purification of biomolecules which are sensitive toward ionic condition [16]”. is replaced with the following references [17] as below in the published article.

The following statement, “During the planning stage, it is crucial to understand the complexity of the physical and chemical interaction reaction throughout the partitioning process in the LBS [21]”. And “Lastly, is to assess the effect of each process parameters on the product recovery and purity [21]”. is replaced with the following references [22] as below in the published article.

The following statement, “Fundamental principles for the formation of LBS requires a phase diagram or also called the binodal curve where these provide a set of information regarding the two-phase formation and their required concentration in the top and bottom phases [22]” is replaced with the following references [23] as below in the published article.

The following statement “A detailed study has been evaluated previously by Iqbal et al., (2016) on the tie line length (TLL) and slope tie line (STL) for the construction of phase diagrams [23]”. should be replaced with reference [24] below in the published article.

The following statement, “Binodal curves can be constructed using three methods namely, turbidometric titration, cloud point, and node determination method for predetermined phase diagram [22,24,25]”. is replaced with the following references [23,25,26] as below in the published article.

The following statement, “The purpose of using polymer-based LBS is that the chemical composition of a non-ionic characteristics toward an ionic environment is compatible towards biomolecules having low ionic strength [16]”. is replaced with the following references [17] as below in the published article.

The following statement, “Aside from that, the phase forming component from polymer-based has the ability to be recycled and reused for subsequent extraction process and this reduces the cost of polymers phase-forming component [26]”. is replaced with the following references [27] as below in the published article.

The following statement, “Polymer-based LBS are commonly used for protein extraction due to its poor hydrophilic and hydrophobic interaction in polymer/salt-based LBS”. should refer to the following reference [14] as below in the published article.

The following statement, “In most work, conventional polymer-based LBS has been replaced by using thermo-separating polymers as the phase-forming component to overwhelm the limitation of polymer-based LBS such as high viscosity and difficulties in recycling process [27,28]”. is replaced with the following references [28,29] as below in the published article.

The following statement, “Thermo-separating polymers are random, di-block, and tri-block co-polymers of ethylene oxide (EO) and propylene oxide (PO) [29]”. is replaced with the following references [30] as below in the published article.

The following statement, “Thermo-separating polymers have a low cloud point temperature (≤47 °C) which is suitable to achieve temperature-induced phase separation where a target protein can be recovered from the polymer [30]”. is replaced with the following references [31] as below in the published article.

The following statement “Ng et al., (2012) reported that the TLL of 41.2% (w/w), volume ratio (VR) of 1.25, pH 7, and crude loading (w/w) of 20% were the optimal conditions to recover cyclodextrins using polymer-based LBS with ethylene oxide–propylene oxide (EOPO) 3900 and two phosphate salts [31]”. should be replaced with reference [32] below in the published article.

The following statement “Another research carried out by Lin et al. [32] with modified method using flotation technique and the combination of PEG 8000 and potassium phosphate salt. The optimum conditions in cyclodextrins (CDs) recovery was optimized at 18% (w/w) PEG 8000 and 7.0% (w/w) potassium phosphate with TLL of 27.2% (w/w), VR of 3.0, pH 7, and crude loading (w/w) of 20%. The experiment showed that the recovery of CDs was affected by alternating each of the parameters such as TLL, VR, and pH where the purification factor (PFT), which corresponded to the highest CGTase purity up to 21.8 with a yield of 97.1%, was recovered in the PEG-rich top phase within a short period [32]”. should be replaced with reference [33] below in the published article.

The following statement “A similar approach utilizing polymer-based LBS was employed for the recovery of lignin peroxidase from Amauroderma rugosum (Blume and T. Nees) [33]”. should be replaced with reference [34] below in the published article.

The following statement, “Ooi et al. (2009) reported a study on purification of lipase from Burkholderia pseudomallei using alcohol/salt-based LBS [19]”. and “The effect of NaCl on lipase partitioning was found to generate an electrical potential difference in the LBS [34]”. should be replaced with reference [20] below in the published article.

The following statement, “Lin et al., (2013) conducted a study using alcohol/salt-based LBS to recover the intracellular human recombinant interferon-α2b (IFN-α2b) from Escherichia coli [34]”. and “As the pH environment in LBS increased, the contaminant protein and IFN protein were partitioned toward water-miscible alcohol top phase. This is mainly due to the negatively charge protein which tends to partition to the top phase and repels from the salt-rich bottom phase [34]”. should be replaced with reference [35] below in the published article.

The following statement, “A recent study conducted on a recyclability test utilizing 1-propanol and ammonium sulfate system for the phlorotannin recovery from Padina australis and Sargassum binderi [35]”. should be replaced with reference [36] below in the published article.

The following statement, “Their remarkable properties such as negligible vapor pressure, low melting point and high thermal stability have received numerous attention from researchers [36,37]”. should be replaced with reference [37,38] below in the published article.

The following statement, “ILs are composed with tuneable physico-chemical properties of cationic and anionic ions [38]”. should be replaced with reference [39] below in the published article.

The following statement, “Thus, replacing ILs as the phase-forming component in LBS would be beneficial for the extraction and purification of specific target biomolecules from complex crude extract [39]”. should be replaced with reference [40] below in the published article.

The following statement, “A review by Ostadjoo et al., (2017) revealed the green and environmentally friendly, 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) for its potential features in the field of lignocellulose biomass dissolution and biopolymer processing [40,41,42]”. should be replaced with reference [41,42,43] below in the published article.

The following statement, “Gutowski et al. (2003) reported that by mixing imidazole-based ILs and a kosmotropic salt (i.e., K₃PO₄) would lead to the formation of a biphasic system [43]”. should be replaced with reference [44] below in the published article.

The following statement, “This research had gained interest investigating the phase separation behavior of IL-based LBS. The study on protein extraction using IL-based LBS in a single step was conducted by Du et al. (2007)” should be referred to reference [45] below in the published article.

The following statements, “Apart from that, Ng et al. (2014) investigated the purification of CGTase from Bacillus cereus fermentation broth in IL/salt LBS, composing of 35% (w/w) of (Emim)BF₄ and 18% (w/w) of sodium carbonate with the addition of 3% (w/w) of NaCl [45]”. and “Ng et al. (2014) also reported that it was crucial in the selection of salt such as citrate and carbonate ions as they played an important role in LBS formation and was able to attract water molecules toward them by forming strong intermolecular interaction [45]”. should be replaced with reference [46] below in the published article.

The following statement, “Chang et al., (2018) used a series of alkyl bromide imidazole for the extraction of C-phycocyanin (CPC) from Spirulina platensis and found that the longer the alkyl chain, C₈MIM-Br enhanced the extraction efficiency of CPC [46]”. should be replaced with reference [47] below in the published article.

The following statement, “This was supported by a recent study that evaluated the protein partitioning in ILs-based LBS composed of Iolilyte 221 PG and citrate salts was found to be feasible but complex depending on various factors such as concentration of phase-forming component, pH, temperature, ionic strength, and chemical nature of the target biomolecules [47]”. should be replaced with reference [48] below in the published article.

The following statement, “Deep-eutectic-solvents (DESs) are defined as a subclass from ILs because of their similarity in physical and chemical properties of ILs [48]”. should be replaced with reference [49] below in the published article.

The following statement, “The behavior exhibited from DESs are contributed from hydrogen bonding, whereas ILs are dominated by ionic interactions [49]”. should be replaced with reference [50] below in the published article.

The following statement, “A major advantage from DESs are their charge delocalization properties which are responsible for the decrease in melting point of mixture relative to the raw material [50]”. should be replaced with reference [51] below in the published article.

The following statement, “By having the similar characteristic as ILs and exhibiting some distinguishing features, including ease of synthesis, low cost, and valuable for industrial application, DESs have gained interest in many fields especially in LBS [51]”. should be replaced with reference [52] below in the published article.

The following statement, “ChCl-based DESs have the same advantages with ILs besides showing excellent biodegradability and low toxicity [52]”. should be replaced with reference [53] below in the published article.

The following statement, “Zeng et al. (2014) had performed the extraction of bovine serum albumin (BSA) using four different kind of DESs, namely, choline chloride (ChCl)-urea, tetramethylammonium chloride (TMACl)-urea, tetrapropylammonium bromide (TPMBr)-urea, and ChCl-methylurea [53]”. should be replaced with reference [54] below in the published article.

The following statement, “A similar work with different DESs was investigated by Pang et al. (2017) using DES-based LBS which composed of choline chloride-polyethylene glycol (ChCl-PEG or DES) and sodium carbonate were applied for the extraction of specific protein (i.e., BSA and papain) [52]”. should be replaced with reference [53] below in the published article.

The following statement, “A modified DES-based LBS using ultrasonic-assisted were employed for the extraction of ursolic acid from Cynomorium songaricum Rupr [54]”. should be replaced with reference [55] below in the published article.

The following statement, “This novel approach of surfactant-LBS has gained interest mainly due to the combination phase which exist in many different forms (i.e., spherical micelles, rod-like micelles, or vesicles) by simply alternating different composition and concentration of surfactants [55]”. should be replaced with reference [56] below in the published article.

The following statement, “The principle of surfactant-based LBS used the cloud point extraction (CPE) system in which the non-ionic surfactant is heated above the cloud point temperature, causing dehydration of detergent for the phenomenon of phase separation to occur [56]”. should be replaced with reference [57] below in the published article.

The following statement, “Surfactant-based LBS composed of 24% (w/w) Triton X-100 and 20% (w/w) xylitol was used for the purification of lipase from pumpkin seeds [57]”. should be replaced with reference [58] below in the published article.

The following statement, “An example of surfactant-based LBS extraction was conducted by Sankaran et al. (2018) using surfactant and xylitol under the optimum operation condition of 25% w/w of xylitol concentration, 15% (w/w) Triton X-100, 80% w/w of crude lipase, 4 mL of top phase, 35 mL of bottom phase, pH 7, and 15 min of flotation time showed the maximum lipase extraction and efficiency of 3.63 and 86.46% [58]”. should be replaced with reference [59] below in the published article.

The following statement, “SS is an adsorptive bubble separation technique introduced by Sebba who suggested that the use of an immiscible thin organic solvent layer overlaid on top of the liquid bulk as a modification of ion flotation [59]”. should be replaced with reference [60] below in the published article.

The following statement, “LBF has accommodated the ease for extraction of high value biomolecules such as protein, lipase, astaxanthin, and betacyanin [8,10,60,61]” should be replaced with reference [8,10,13,61] below in the published article.

The author would like to clarify the misplace of author’s last name (First name: Preshna, Last name: Mathiazakan) in the following statement “Preshna et al., (2016) had reported that the pilot-scale alcohol/salt LBF system acquired a purification factor of 12.2, efficiency of 88%, and a recovery yield of 93.27% which was feasible for purification of lipase to be implemented into the industrial scale processes [62]”. should be replaced with Mathiazakan et al. (2016). The following reference of the statement remains the same.

The authors would also like to clarify the following statement “A recent study conducted by Sankaran et al. (2018) utilized the application of ultrasound-assisted LBS for extraction of protein from Chlorella vulgaris FSP-E microalgae [12]”. should be replaced with reference [6] below in the published article.

The following statement, “On the other hand, low molecular weight polymer will decrease the purification factor for target biomolecules as it will be partitioned together with contaminant proteins at the polymer-rich top phase [31,32]”. should be replaced with reference [32,33] below in the published article.

The following statement, “The effect of molecular weight has been discussed with the used of polymers such as PEG and potassium phosphate salt for the recovery of cyclodextringlycosyltransferase (CGTase) from Bacillus cereus [32]” should be replaced with reference [33] below in the published article.

The following statement, “To improve the recyclability of phase-forming component in the LBS process, another similar research replaced using thermo-separating polymer (EOPO) as the phase component for the purification and recovery of CGTase [31]”. should be replaced with reference [32] below in the published article.

The following statement, “Few studies had shown that a high saturation level of salt concentration will cause a reduction in solubility of target biomolecules due to the higher salting-out ability of salt [20,36]”. should be replaced with reference [21,37] below in the published article.

The following statement, “According to the Hofmeister series, the salting-out ability of anions are arranged in the following order: SO₄²⁻ > HPO₄²⁻ > citrate³⁻ > F⁻ > Cl⁻ > Br⁻ >I⁻ > NO³⁻ > ClO⁴⁻ [25]. “should be replaced with reference [26] below in the published article.

The following statement, “As a conclusion, the extraction of protein is more favorable in the alcohol-rich top phase with increasing partitioning coefficient (K) when a low molecular weight salts is used [18,34]”. should be replaced with reference [19,35] below in the published article.

The following statement, “The effect of temperature on the extraction efficiency of CPC from Spirulina platensis microalgae was studied and the maximum extraction efficiency up to 99.0% was achieved near the temperature range of 308 K [46]”. should be replaced with reference [47] below in the published article.

The following statement, “It was found that lowering the temperature to 298 K caused the rate of CPC recovery to decrease, resulting in a low extraction efficiency. The influence of temperature on extraction efficiency study of BSA and papain was evaluated [52]” should be replaced with reference [53] below in the published article.

Corresponding to Table 1, the following references should be adjusted as per below:

• Reference [31] should be replaced with reference [32],
• Reference [32] should be replaced with reference [33],
• Reference [33] should be replaced with reference [34],
• Reference [34] should be replaced with reference [35],
• Reference [19] should be replaced with reference [20],
• Reference [35] should be replaced with reference [36],
• Reference [45] should be replaced with reference [46],
• Reference [46] should be replaced with reference [47],
• Reference [53] should be replaced with reference [54],
• Reference [52] should be replaced with reference [53],
• Reference [54] should be replaced with reference [55],
• Reference [57] should be replaced with reference [58],
• Reference [58] should be replaced with reference [59].

With this correction, the order of some references has been adjusted accordingly. The authors state that the scientific conclusions are unaffected. This correction was approved by the Academic Editor. The original publication has also been updated.